Chapter II: Introduction: TO

SHELL-BEARING BRITISH MOLLUSCA.

A common garden Snail, observed crawling and feeding, is easily seen to possess a distinct head, upon which are four feelers or horns, with eyes at the end, and underneath which is a mouth; a broad disc, extending the whole length of the body, is the organ of locomotion; a spiral or coiled shell surmounts the whole.

If, on the other hand, an Oyster be opened, no distinct head, or place for eyes or mouth, can be seen, but only a seeming mass of pulp, with a round gristle in the centre (the muscle of attachment), the former enclosed in a soft skin with a double fringe round the edge (mantle), placed within a shell composed of two pieces.

All Mollusca are more or less completely represented by these two. The Snail and its class are named _Gasteropoda_ (abdomen-creeping), and their shells _Univalves_; the Oyster and its class, _Acephala_ (headless), and their shells _Bivalves_. We begin with the latter class at--

PLATE I.

_Pholadidæ_, or "Borers," 1-13, have the power of piercing and inhabiting holes in submarine wood, rocks, and stones. The hinder part of the body is lengthened out in the form of a double tube, with openings for the ingress and egress of fluids. _Teredo_, 1-6, has short valves, two pallets fixed at the sides of the siphons, and lines its hole with a shelly tube. _Pholas_ and _Pholadidea_, 8-13, have long valves and sometimes accessory plates. The shell of _Xylophaga_, 7, is like that of _Teredo_, but the animal has neither pallets nor tube.

_Gastrochæna_, 14, has a gaping shell, and encloses itself in a bottle-shaped covering of cemented stones and sand. _Saxicava_, 15, 16, _Venerupis_, 18, and _Petricola_, 17, burrow in sand, or live in holes of rocks.

_Myadæ_, or "Gapers," _Mya_, 19, 20, and _Panopæa_, 21, 21*, burrow downwards in sand and mud, their siphons protected by a coriaceous covering. Their shells are not closed all round, and those of _Mya_ have a spoon-shaped process in the hinge of one valve.

_Corbulidæ_, 22-28, have short siphons with fringed edges, and the foot protrudes through a hole in the otherwise closed mantle.

PLATE II.

_Poromya_, 1, 1*, and the beautiful pearly _Pandora_, 2, 3, might be included in the family of _Corbulidæ_. _Lyonsia_, 4, and _Thracia_, 5-10, represent the _Anatinidæ_. 11-18 are _Solenidæ_, or "Razor-shells." Solens burrow in deep holes in the sand, where they remain in a perpendicular position at a great depth below the surface, where yet their presence may be traced by the opening left. Their large muscular foot enables them to take great leaps when out of the holes.

PLATE III.

_Psammobia_, 1-4, and _Tellina_, 5-16, include some of our most beautiful shells. The animals have a large, fleshy, curved foot, and the mantle open and fringed. Their shells are provided with an external ligament, and teeth on the hinge. _Donax_, or "Wedge," 19, 20, has long, separated, fringed siphons. Besides the small external ligament, properly so called, the _Mactridæ_ have a triangular pit in the hinge of their shell, containing an elastic substance or spring, designed to resist the action of the adductor muscles. _Mactra_, 21-26, ends the Plate.

PLATE IV.

_Lutraria_, 1-3, is another genus of _Mactridæ_. The _Veneridæ_, 4-16 and 23, or "Venus" tribe, differ from it in not having the spring-holding pit. _Artemis_, 10, 11, is known by a large angular bend in the pallial impression; and _Cytherea_, 23, is distinguished from Venus by one tooth on the hinge standing out a little way from the central ones. _Astarte_, 17-22, belongs to the _Cyprinidæ_.

PLATE V.

Fig. 1-3 also represent genera of _Cyprinidæ_. They have no bend in the palleal impression. _Cardium_, or "Cockle," 4-13, presents a peculiarity in the foot, which is large and bent, and enables the animal to leap in a very lively manner. The family of _Lucinidæ_ occupy the remaining figures. _Lucina_ has a curious tongue-shaped doubling of the pallial impression.

PLATE VI.

The _Kelliadæ_, 1-15, are marine, while the _Cycladidæ_, completing the Plate, are fresh-water bivalves, and may be found in many ponds and rivers.

PLATE VII.

Of the _Unionidæ_, or "Fresh-water Mussels," _Unio_, 1-3, has teeth on the hinge, and _Anodon_, 4, has not: it is a thin shell. The foot of these molluscs is very large, and is used in cutting the animal's way through the mud in which it burrows. Of the marine, or true Mussels, _Modiola_, 6-9, and _Crenella_, 12-17, have a portion of the shell reaching beyond the point or apex, which in _Mytilus_ is terminal, 18-21. _Dreissina_, 5, is shaped like _Mytilus_, but lives in fresh-water docks. The _Mytilidæ_ attach themselves by means of horny threads spun from the foot, and called a "byssus."

PLATE VIII.

Shells of _Arcadæ_, 1-14, have the hinge characterized by a series of teeth on each side of the apex. _Nucula_, _Arca_, and _Pectunculus_ are easily distinguished. _Limopsis_, 14, has a spring pit between the two rows. Our figure of _Pinna_, 16, is from a young specimen: it grows to great size, and spins a very silky byssus. The shell of _Anomia_, 18, is fixed to rocks, etc., by means of a bony button passing through a hole or sinus in the lower valve. _Lima_, 22-24, has a light, thin shell, and its mantle is adorned with beautiful fringes. It swims rapidly through the water by the opening and shutting of its valves, and also has the habit, in seasons of rest, of protecting itself by a network or vest of marine fragments strung together by its byssal threads.

PLATE IX.

Contains the shells of our Pectens, or Scallops, 1-16. The animals swim like _Lima_, as above, and also spin a byssus.

The class _Brachiopoda_, 17-24, so named because what seem to be organs of locomotion consist of a pair of coiled, ciliated arms, ends the list of Headless Molluscs and their bivalve shells.

PLATE X.

Class _Pteropoda_, 1-4, contains minute Mollusca, with glassy shells variously formed, and wing-like expansions for swimming.

_Chiton_, 5-17, or "Coat of Mail," which may often be seen incrusting rocks, commences the _Gasteropoda_; although seemingly fixed, they are capable of locomotion, using the whole of the oval disc, which may be seen on turning them over, for the purpose. The same may be said of the "Limpet" tribe, _Patella_, 1-22.

PLATE XI.

This Plate commences with other forms of the Limpet tribe, _Fissurella_, 1, 2, with a hole at the top; _Puncturella_, 3, with a fissure near the top; and _Emarginula_, 4-6, with a slit at the margin. _Haliotis_, 7, or pearly "Ear-shell," leads to the _Trochidæ_, or "Tops," 8-27.

PLATE XII.

_Ianthina_, 1-4, is genus of oceanic molluscs, which are provided with a beautiful floating apparatus, on which the female carries her egg-bags.

_Neritina_, 5, and the _Paludinidæ_, 8-11, live in fresh-water. The animal of _Paludina_ is sprinkled all over with bright, golden specks. The _Littorinæ_, or "Winkles," 12-24, are marine, and frequent the shore among seaweeds. _Lacuna_, 25-32, belongs to the same family.

PLATE XIII., XIV.

Are small genera, various in their characters and habits, but reasonably included in the last family, _Littorinidæ_.

PLATE XV.

The animals of _Turritella_, 1-3, and _Cæcum_, 6, 7, are not unlike, although the shells are so different; eyes at the base of the tentacles, a short foot, and horny operculum. The somewhat similar animal of _Aporrhais_, 4, 5, is brilliantly coloured with gold and red. _Cerithium_, 8-10, differs from _Cerithiopsis_, 11-15, more in regard to the animal than the shell; the latter animal has a retractile proboscis, and its operculum is not spiral.

PLATE XVI.

_Chemnitzia_, 1-11, and _Truncatella_, 12, together with _Stylifer_, _Eulima_, and _Odostomia_, form the family of _Pyramidellidæ_. Notwithstanding the difference in the shells, the animals are very similar, having a retractile proboscis, and eyes immersed at the base of their tentacles.

The animal of _Natica_, 13-19, has a lobe on the upper part of the foot, reflected over the shell in front, and another lobe behind. The shells of _Laminaria_, 23, 24, are completely enveloped in similar lobes.

PLATE XVII.

The shells of _Odostomia_ are known by a fold in the inner lip of the aperture.

PLATE XVIII.

Two _Tritons_, 1, 2, are admitted for the first time as British, on what we consider fair evidence, although only two or three specimens have been taken off Guernsey. One of _T. nodiferus_ was incrusted by a truly British _Lepralia_. _Murex_, 3, is now familiar as an aquarian, as well as _Purpura_, 5. A milky secretion found in the head turns purple when exposed, and gives the celebrated purple dye. _Buccinum_, 7-13, includes the common "Whelk," 8. _Fusus Berniciensis_, 14, is among the rarest and most beautiful of our British shells.

PLATE XIX.

_Nassa reticulata_, 3, is a favourite inhabitant of the tank; it burrows in search of food among the pebbles, elevating its siphon above the surface. _Mangelia_, 4-26, has a similar long siphon. The shell of _Erato_, 27, is wrapped in the lobes of the animal's mantle, as is also that of _Cyprea_, 28, the latter presenting a beautiful object.

PLATE XX.

After _Tornatella_, 1, and _Ovula_, 2, 3, come _Bullidæ_, 4-27, including several genera differing remarkably in the shape and disposition of the lobes of their mantles, which in some instances, as in _Philine_, 20-25, cover the shell. The stomach of _Scapander_, 26, 27, is a remarkable kind of mill, composed of two bones, between which the food is ground. The shells of _Aplysia_, 28, and _Pleurotranchus_, 29, 30, are quite internal. _Spirula_, 31, belonging to the Cephalopodous or Cuttlefish tribe, is only introduced doubtfully, as there is no proof of the species living in our seas.

PLATE XXI., XXII., XXIII., XXIV.

These are occupied by shells of _Gasteropoda pulmonifera_, so named because they breathe air by a pulmonary cavity, instead of water by gills. The _Limnæadæ_, or fresh-water Snails, contained in Plate I., live in water, but breathe by exposing the pulmonary cavity to air at the surface. _Succinea_, Plate XXII., 1-3, lives by the sides of streams, sometimes immersed. _Conovulus_, 4-7, affects brackish marshes. Our common Slugs yield, on dissection, thin shells, which are concealed beneath the mantle, _Limax_, 9-12. The shells of _Testacellus_, 13, 14, are fixed near the end of the foot, outside. The glassy shells of _Vitrina_, 15, 16, do not enclose the whole Slug-like animal. The other genera of Land Snails have shells large enough to receive the animal when retracted and withdrawn for repose.

* * * * *

BRITISH FOSSIL SHELLS.

The following living species are also found in a fossil state in drift and strata of the British Isles. They are all enumerated in Mr. Searles Wood's monograph of the CRAG Mollusca.

The numbers refer to the species as figured in our Plates, Mr. Wood's nomenclature being inserted in italics when differing from ours.

Pl. I. Teredo 2. Pholas 11. Pholadidea 12. Gastrochæna 14, as _dubia_. Saxicava 15, 16. Venerupis 18. Mya 19, 20. Panopea 21, 21*, as _Faujasii_. Corbula 22, 23? Sphænia 25. Neæra 27.

Pl. II. Poromya 1. Pandora 2, as _inæquivalvis_, 3, as _pinna_. Thracia 7, 8. Solen, 13, 15. Solecurtus 18, as _Mactra strigilata_. Syndosmya, as _Abra_, 19, 22.

Pl. III. Psammobia 1, 3, 4. Tellina 5, 6, 7, 9, as _ovata_, 15, as _Balthica_, 16. Scrobicularia 18, as _Trigonella plana_. Donax 19, as _vittatus_. Mactra 20, 21, 22, as _ovalis_, 23, 25, 26.

Pl. IV. Lutraria 2. Tapes 7, 8. Artemis 11. Venus 12, 14, 15, 17. Astarte 18, 19, 20, 22, as _borealis_.

Pl. V. Cyprina 1. Circe 2. Isocardia 3. Cardium 6, 8, 9, 12, 13. Lucina 14, as _Loripes_, 15, as _Cryptodon flexuosum_, 16. Diplodonta 19. Clausina 20, as _Cryptodon f._

Pl. VI. Montacuta 1, 2, 3. Kellia 5, 6. Poronia 7, as _Kellia r._ Cyclas 16, 18. Pisidium 23, 24, 25, 26.

Pl. VII. Unio 2, 3. Anodon 4. Modiola 6, 9, 10. Crenella 13, 14, 15, 16. Mytilus 18, 19, 20.

Pl. VIII. Nucula 1, 5. Leda 6, 7. Area 9, 10, 11, as _pectunculoides_. Pectunculus 13. Avicula 15. Pinna 16. Ostrea 17. Anomia 18, 19, 20, 21. Lima 22, 23, 24.

Pl. IX. Pecten 1, 2, 5, 8, 9, 10, 11, 12, 13, 14.

Pl. X. Chiton 7, as _fascicularis_. Patella 18. Acme 23. Propilidium, as _Tectura_, 24. Dentalium 26, 27. Capulus 28. Calyptræa 29.

Pl. XI. Fissurella 1, as _græca_. Puncturella 3. Emarginula 5, 6. Trochus 8, 10, 11, 12, as _papillosus_, 15, 16, 17, 19. Margarita 21. Adeorbis 25. Scissurella 26.

Pl. XII. Paludina 9. Valvata 10. Littorina 14. Lacuna 27.

Pl. XIII. Rissoa 3*, as _Paludestrina subumbilicata_, 7, 11?, 13?, 15, 23, 27.

Pl. XIV. Rissoa 2, 9, as _Chemnitzia_. Aclis 24, as _Alvania ascaris_, 25, as _Chemnitzia n._

Pl. XV. Turritella 2. Aporrhais 4. Cæcum 6, 7. Cerithium 9, 10. Cerithiopsis, as _Cerithium_, 11. Scalaria 17, 19, 20. Eulima 22, 25.

Pl. XVI. Chemnitzia 1, 2, as _similis_, 4, 8. Natica 13, 17, as _Catena_, 19, as _Groenlandica_. Velutina 21. Trichotropis 26.

Pl. XVII. Odostomia 1, 8, as _plicata_, 9, as _plicata_, 10?, 12.

Pl. XVIII. Purpura 5. Buccinum 10? Fusus 15, as _Trophon_, 16, as _Tr._, 17, as _Tr. gracile_, 18, as _Tr. T._, 19, as _Tr. p._ Trophon 22, 24.

Pl. XIX. Nassa 1, 2. Mangelia, as _Clavatula_, 4, 5, 8, as _Philberti_, 9, 11, as _Boothii_, 12, 14, 15, 17?, 21, 22. Erato 27. Cypræa 28.

Pl. XX. Tornatella 1, as _Actæon tornatilis_. Ovula 3, as _Bulla_. Cylichna, as _Bulla_, 4, 5, as _regulbiensis_, 7, 9, 12. Bulla 19. Philine as _Bullæa_, 21, 22. Scaphander, as _Bulla_, 26.

Pl. XXI. Limnæa 1, 4, 7, 11. Planorbis 18, 24, as _complanatus_, and in the upper fresh-water formation, all except 9, 11.

Pl. XXII. Succinea 1, 3. Conovulus 5, and in the more recent fresh-water deposits, all except 7 and 13 to 16.

Pl. XXIII. Helix 19, 22, and upper fresh-water, all except 1, 12, 14, 15, 24, 25, 26.

Pl. XXIV. Upper fresh-water deposits, all except 16, 24.

* * * * *

INDEX TO THE GENERA.

Referring to Plates and Figures.

Achatina, XXIV. 24.
Aclis, XIV. 23, 25.
Acmæa, X. 22, 23.
Acme, XXIV. 26.
Adeorbis, XI. 25.
Akera, XX. 16.
Amphispira, XX. 14, 15.
Ancylus, XXI. 14-17.
Anodonta, VII. 4.
Anomia, VIII. 18-21.
Aplysia, XX. 28.
Aporrhais, XV. 4, 5.
Arca, VIII. 18-12.
Argiope, IX. 20, 23.
Artemis, IV. 10, 11.
Assiminea, XIII. 1, 2.
Astarte, IV. 17, 22.
Avicula, VIII. 15.
Azeca, XXIV. 23.

Balea, XXIV. 17.
Barleeia, XIV. 12.
Bithinea, XII. 6, 7.
Buccinum, XVIII. 8-13.
Bulla, XX. 17-19.
Bulimus, XXIV. 1-4.

Calyptræa, X. 29.
_Capulus_, Pileopsis.
Cardium, V. 4-13.
Carychium, XXII. 8.
Cæcum, XV. 6-7.
_Cemoria_, Puncturella.
Ceratisolen, II. 11.
Cerithiopsis, XV. 11-15.
Cerithium, XV. 8-10.
Chemnitzia, XVI. 1-11.
Chiton, X. 5-17.
Circe, V. 2.
_Clavatula_, Mangelia.
Clausilia, XXIV. 18-21.
Clausina, V. 20-22.
Cochlodesma, II. 10.
Conovulus, XXII. 4-7.
Corbula, I. 22-24.
Crania, IX. 24.
Crenella, VII. 12-17.
Cyclostoma, XXIV. 25.
Cyclas, VI. 16-20.
Cylichna, XX. 4-13.
Cypræa, XIX. 28.
Cyprina, V. 1.
Cytherea, IV. 23.

Dentalium, X. 26, 27.
Diodonta, II. 16, 16*.
Diplodonta, V. 19.
Donax, III. 19, 20.
Dreissina, VII. 5.

Emarginula, XI. 4-6.
Euomphalus, XIV. 17, 18.
Ervillia, III. 17.
Eulima, XV. 22-26.
Eulimella, XIV. 26-30.

Fissurella, XI. 1, 2.
Fusus, XVIII. 14-19.

Galeomma, VI. 14, 15.
Gastrochæna, I. 14.

Haliotis, XI. 7.
_Helix_ (Zonites), XXII. 17-29.
Helix, XXIII. 1-29.
_Hinnites_, Pecten, IX. 1.
Hippothyris, IX. 17.
Hyalæa, X. 1.

Ianthina, XII. 1-4.
Isocardia, V. 3.

Jeffreysia, XIV. 13-16.

Kellia, VI. 5-8.

Lachesis, XVIII. 6.
Lacuna, XII. 25-32.
Lamellaria, XVI. 23, 24.
Leda, VIII. 6, 7.
Lepton, VI. 9-13.
Lima, VIII. 22-24.
Limax, XXII. 9-12.
Limnæa, XXI. 1-11.
Limopsis, VIII. 14.
Littorina, XII. 12-24.
Lucina, V. 14-18.
Lucinopsis, IV. 9.
Lutraria, IV. 1-3.
Lyonsia, II. 4.

Mactra, III. 21-26.
Mangelia, XIX. 4-26.
Margarita, XI. 21-24.
_Marginella_, Erato.
_Megathyris_, Argiope.
Modiola, VII. 6-11.
Montacuta, VI. 1-3.
Murex, XVIII. 3, 4.
Mya, I. 19-20.
Mytilus, VII. 18-21.

Nassa, XIX. 1-3.
Natica, XVI. 13-19.
Neæra, I. 26-28.
Neritina, XII. 5.
Nucula, VIII. 1-5.

Odostomia, XVII. 1-31.
Ostrea, VIII. 17.
Otina, XVI. 25.
Ovula, XX. 2, 3.

Paludina, XII. 8, 9.
Pandora, II. 2, 3.
Panopæa, I. 21, 21*.
Patella, X. 18-21.
Pecten, IX. 1-16.
Pectunculus, VIII. 13.
Petricola, I. 17.
Phasianella, XI. 27.
Philine, XX. 20-25.
Pholas, I. 8-11, 13.
Pholadidea, I. 12.
Physa, XXI. 12, 13.
Pileopsis, X. 28.
Pilidium, X. 24.
Pinna, VIII. 16.
Pisidium, VI. 21-28.
Planorbis, XXI. 18-28.
Pleurobranchus, XX. 29.
_Pleurotoma_, Mangelia.
Poromya, II. 1, 1*, IX.
Propilidium, X. 25.
Psammobia, III. 1-4.
Puncturella, XI. 3.
Pupa, XXIV. 5-16.
Purpura, XVIII. 5.

Recluzia, XVI. 20.
Rissoa, XIII. 3-28; XIV.

Saxicava, I. 15, 16.
Scalaria, XV. 16-20.
Scaphander, XX. 26, 27.
Scrobicularia, III. 18.
Scissurella, XI. 26.
_Segmentina_, Planorbis, XXI. 27, 28.
Skenea, XIV. 19-22.
Solen, II. 12-15.
Solecurtus, II. 17, 18.
Spirialis, X. 2-4.
Spirula, XX. 31.
Stylifer, XV. 21.
Succinea, XXII. 1-3.
Syndosmya, II. 19-22.
Sphænia, I. 25.

Tapes, IV. 4-8.
Tellina, III. 5-16.
Terebratula, IX. 18-20.
Teredo, I. 1-6.
Testacellus, XXII. 13, 14.
Thracia, II. 5-9.
Tornatella, XX. 1.
Trichotropis, XVI. 26.
Triton, XVIII. 1, 2.
Trochus, XI. 8-20.
Trophon, XVIII. 20-24.
Truncatella, XVI. 12.
Turritella, XV. 1-3.
Turtonia, VI. 4.

Unio, VII. 1-3.

Valvata, XII. 10, 11.
Velutina, XVI. 21, 22.
Venerupis, I. 18.
Venus, IV. 12-16.
_Vertigo_, Pupa.
Vitrina, XXII. 15-16.

Xylophaga, I. 7.

Zonites, XXII. 17-29.
Zua, XXIV. 22.

PLATE I.

TEREDO. Pierces and inhabits wood.

Fig.

1. T. NAVALIS, _Linn._--_T. Batavæ._--Herne Bay, R. Pallets shelly, crescented; valves with auricles extended sidewise; tube long.

2. T. NORVEGICA, _Spengl._--_T. Bruguieri._--Port Patrick, Teignmouth, etc., Mc. Pallets shelly, not crescented; auricles not extended.

3. T. MEGOTARA, _Hanl._--_T. nana_ (young).--Herne Bay, Devon, Swansea, etc., R. Pallets shelly, spade-shaped; auricles raised and expanded.

4. T. BIPENNATA, _Turt._--Ireland, Scarborough, etc., R. Pallets horny, long; auricles lobed.

5. T. MALLEOLUS, _Turt._--Torquay, Rr. Pallets shelly, mallet-shaped; valves narrow.

6. T. PALMULATA, _Lamk._--_T. bipalmulata._--Floating wood, Ire., S. Eng. Pallets horny, short; valves small, shaped like _T. navalis_.

XYLOPHAGA. In fixed and floating timber.

7. X. DORSALIS, _Turt._--Ayrs., Dubl., Exm., Scarb., etc., C. Two dorsal plates, no tube, no pallets.

PHOLAS. Pierces and inhabits stone.

8. P. DACTYLUS, _Linn._--_P. hians_, _P. callosa_.--Eng., Scot., Ire., C. Dorsal plates four; hinge pitted.

9. P. CANDIDA, _Linn._--Eng., Scot., Ire., C. One dorsal plate; valves not beaked.

10. P. PARVA, _Penn._--_P. callosa_, _P. tuberculata_.--Salcombe, Belfast, Cornwall, etc., M. C. One dorsal plate; valves beaked.

11. P. CRISPATA, _Linn._--_P. bifrons._--Hastings, Liverp., Scarb., Dubl., Forth, etc., C. No dorsal plate; valves broad, beaked, with oblique division.

13. P. STRIATA. Rare and doubtful as British. Valves closed.

PHOLADIDEA. Pierces and inhabits stone.

12. P. PAPYRACEA, _P. Loscombiana_, _P. Goodalli._--S. Devon, N. Ire., R. Valves closed, with a cup. _P. lamellata_, Turt., when young, not closed; no cup.

GASTROCHÆNA. Bores and inhabits stone, thick shells, etc.

14. G. MODIOLINA, _Lamk._--_G. Pholadia_, _G. hians_, _Mya dubia_, _Mytilus ambiguus_, _Pholas faba_.--Torbay, Birterbuy, Galway, Weymouth, etc. Valves thin, gaping, enclosed in bottle-shaped tube.

SAXICAVA. Bores and inhabits stone.

15. S. RUGOSA, _Linn._--_Mytilus r._, _Hiatella r._, _S. gallicana_, _S. pholadis_, _Byssomya pholadis_, _Mya byssifera_.--Eng., Scot., Ire., C. Valves oval.

16. S. ARCTICA, _Linn._--(_Mya_) _Hiatella a._, _Anatina a_., _Hiatella minuta_, _Solen minutus_, _S. rhomboides_, _Agina purpurea_, _Solen p._--Eng., Scot., Ire., C. Valves rhomboidal; angle serrated.

_Omitted._--S. fragilis, _Nyst._ _Not_ the young of _S. rugosa_. Vigo Bay.

PETRICOLA. Inhabits stone.

17. P. LITHOPHAGA, _Retz._--_P. striata_, _costellata_, _rocellaria_, _ruperella_, Lamk., _Mya_ and _Sphænia decussata_.--Cork, Bristol, R. as British.

VENERUPIS. Bores and inhabits stone.

18. V. IRUS, _Linn._ (Donax).--_Tellina cornubiensis_, _Cuneus foliaceus_, _Petric._, and _Pullastra_, I.--In limestone at Plymouth and other southern coasts. Wedge-shaped.

MYA. Burrows in mud and sand.

19. M. TRUNCATA, _Linn._--_M. ovalis_ and _Sphænia Swainsoni_ (young).--Various localities and depths, C. Truncated at end.

20. M. ARENARIA, _Linn._--Herne Bay, Portsmouth, etc., C. Tapering at end.

PANOPÆA. Burrows in mud.

21. P. NORVEGICA, _Spengl._--_P. glycimeris_, _P. arctica_.--Scarborough, Zetland (90 fath.), Rr. Quadrate.

21*. P. ALDROVANDI, _Lamk._--Cornwall, one specimen, _Jeffreys_. Oblique.

CORBULA. Dredged in mud and sand.

22. C. NUCLEUS, _Lamk._--_C. striata_, _Mya_, and _C. inæquivalvis_.--Dublin, Torquay, Forth, 4 to 80 fath., C. Valves unequal, beaked.

23. C. ROSEA, _Brown_.--Weymouth, Rr. as Brit. Valves not beaked.

24. C. OVATA, _Forbes_.--Isle of Man, Rr. Oval, truncated at end.

SPHÆNIA. Burrows in foliaceous shells.

25. S. BINGHAMI, _Turt._--_Corbula B._--Torquay, Guernsey, Swansea, Forth, etc., R.

NEÆRA. Lives incrusted in sand.

26. N. COSTELLATA, _Desh._--_Corbula c._, _N. sulcata_.--Loch Fyne, Rr. Radiately 3-ribbed.

27. N. CUSPIDATA, _Olivi_.--Forth, Northumberland, Cape Clear, etc., Mr. Pear-shaped.

28. N. ABBREVIATA, _Forbes_.--Loch Fyne, Mc. Radiately 1-ribbed.

PLATE II.

POROMYA. On mud, in deep water.

Fig.

1. P. GRANULATA, _Nyst._--_P. anatinoides_, Forbes.--Skye, R.

1*. P. SUBTRIGONA, _Jeffreys_.--Shetland, Mr. Minute, posteriorly expanded. See Pl. IX.

PANDORA.

2. P. ROSTRATA, _Lamk._--_Tellina inæquivalvis_, Linn.; _P. margaritacea_ and _inæquivalvis_.--S. Devon?, Guernsey, R. as Brit. Valves long.

3. P. OBTUSA, _Leach_.--_Solen Pinna_, Mont.--S. Devon, Dorset, Mc. Ire., R. Valves short and broad.

LYONSIA. With byssal attachment.

4. L. NORVEGICA, _Chemn._--_Mya_ and _Anatina n._, _Mya_ and _Anatina striata_, _M. nitida_, _Lyonsia elongata_, _Myatella_, and _Osteodesma_.--Tenby, Bantry, Oban, etc., 5 to 80 fath. With movable ossicle on hinge.

THRACIA. Laminarian and Coralline.

5. T. DISTORTA, _Mont._--(_Mya_) _Anatina_ and _Amphidesma d._, _Th. truncata_.--Distribution general, but not common. Short, truncated, irregular.

6. T. CONVEXA, _Wood_.--(_Mya_) _Anatina_ and _Amphidesma c._, _T. declivis_.--S. Devon, Bantry Bay, Arran, etc., Mc. Inflated.

7. T. PHASEOLINA, _Lamk._--_Amphidesma p._, _T. declivis_.--Various localities and depths, C. Oval, obliquely truncated.

8. T. PUBESCENS, _Pult._--(_Mya_) _Anatina_ and _Amphidesma p._, _T. declivis_.--S. Devon, Cornwall, Belfast, etc., C. Oblong, straightly truncated.

9. T. VILLIOSULCA, _Macgillivray_.--_T. ovata_, Brown.--Exmouth, Swansea, Bantry Bay, etc. Various depths, Mc.

COCHLODESMA. Laminarian and Coralline.

10. C. PRÆTENUE, _Pult._--(_Mya_) _Anatina_, _Ligula_, and _Amphidesma pr._--Dorset, Devon, Man, Bantry B., Oban, etc., (25 to 60 fath.), R. Spoon-shaped process on hinge.

CERATISOLEN. Burrows in sand.

11. C. LEGUMEN, _Linn._--(_Solen_) _Psammoiia_ and _Solenicurtus l._--Exmouth, Swansea, Bantry, etc., C. Hinge nearly central.

SOLEN. Burrows perpendicularly in sand.

12. S. PELLUCIDUS, _Penn._--Various British localities, 6 to 100 fath. Curved; hinge not terminal.

13. S. ENSIS, _Linn._--Eng., Scot., Ire., generally 5 to 15 fath., C. Arched and slender.

14. S. MARGINATUS, _Pult._--_S. vagina_, Penn., not Linn.--Exmouth, Clyde, Cork, etc., littoral to 10 fath., Mc. Straight, with terminal constriction.

15. S. SILIQUA, _Linn._--_S. novacula_, _S. ligula_.--Eng., Scot., Ire., many places; littoral and laminarian, C. Straight, end not constricted.

DIODONTA.

16. D. FRAGILIS, _Linn._--(_Tellina_) _Psammobia f._, _Tellina jugosa_ and _ochroleuca_.--Dublin, Tenby, Weymouth, R. Oval or wedge-shaped.

16*. D. BARLEEI, _Jeffr._--Arran, Rr. Minute, subquadrate.

SOLECURTUS.

17. S. COARCTATUS, _Gmel._--_S. cultellus_, _S. emarginatus_, _S. antiquatus_, etc.--Torbay, Anglesea, Man, Skye, etc., R. Oblong, smooth.

18. S. CANDIDUS, _Renieri._--(_Solen_) _S. strigilatus_, Turt., not Linn., _Psammobia scopula_.--S. Devon, Dublin, etc., R. Striated.

SYNDOSMYA.

19. S. PRISMATICA, _Mont._--(_Ligula_) _Mya_ and _Amphidesma p._--Weymouth, Forth, Dublin, Antrim, etc., littoral, Mc. More pointed and narrow than _S. intermedia_.

20. S. TENUIS, _Mont._--(_Mactra_) _Amphidesma t._--Dorset, Scarborough, Antrim, etc., 5 to 100 fath., Mc. Short, subtrigonal.

21. S. INTERMEDIA, _Thompson._--_Mya_ and _Syndosmya nitida_, _Abra profundissima_.--In mud, 6 to 100 fath., Zetland, Skye, Cape Clear, etc., R. Broader and more pointed than _S. prismatica_.

22. S. ALBA, _Wood._--(_Mactra_) _M._ and _Amphidesma Boysii_ and _A. album_.--Brit. co. generally, C. Short, rounded, oval.

PLATE III.

PSAMMOBIA. Inhabits sand and mud.

Fig.

1. P. FERROENSIS, _Chemn._--(_Tellina_) _T. incarnata_, _T. radiata_, _T. trifasciata_, _T. truncata_.--Brit. co. generally; coralline, C. Oblong, keeled and angulated behind.

2. P. COSTULATA, _Turt._--_P. discors._--Torbay, Cornwall, Skye, etc., R. Ribbed behind.

3. P. TELLINELLA, LAMK.--_P. florida._--Exmouth, Guernsey, Tenby, Bantry B., Oban, Zetland, etc., 5 to 50 fath., C. Oval, smooth.

4. P. VESPERTINA, _Chemn._--(_Lux V._) _Solen_, _Sanguinolaria V._, _Tellina depressa_, _variabilis_.--Weymouth, Scarborough, Tenby, Bantry, etc., Guernsey, C. Not angular nor keeled behind.

TELLINA.

5. T. CRASSA, _Penn._--_T. maculata_, _T. rigida_.--S. Devon, Guernsey, Man, Tenby, Bantry, Forth, etc., low-water to 15 fath., C. Thick, orbicular.

6. T. BALAUSTINA, _Linn._--Birterbuy, Skye, Exmouth, Rr. as British.

7. T. DONACINA, _Linn._--_T. trifasciata_, _T. variegata_, _T. Llantivyi_.--Various British loc., and S. Europe, 5 to 50 fath., C. Wedge-shaped.

8, 9. T. PROXIMA, _Brown._--Var. _T. calcarea_ (9), _T. ovalis_, _T. sordida_, _Sanguinolaria sordida_, _Macroma tenera_.--Skye, etc., R.

10, 11. T. PYGMÆA, _Phil._--Devon, Cork, Shetland, etc., 8 to 50 fath., C. Smaller, more convex, and more truncate than _T. donacina_.

12, 13. T. TENUIS, _Da Costa._--_T. planata_, _T. polita_, _T. exigua_.--On sandy shores, in various localities, C. Flat, thin.

14. T. INCARNATA, _Linn._--_T. squalida_, _T. depressa_.--Devon, Bantry, Tenby, R. Flat, beaked.

15. T. SOLIDULA, _Pult._--_T. rubra_, Da Costa, _T. carnaria_, _T. zonata_, _Psammobia solidula_, _T. Balthica_.--All British coasts; littoral, C. Thick, inflated.

16. T. FABULA, _Gronovius._--_T. discors._--On sandy shores generally, C. Valve with oblique striæ (omitted by error).

ERVILLIA.

17. E. CASTANEA, _Mont._--(_Donax_) _Mesodesma c._, _Capsa c._--Cornwall and Scilly Isles, R. Ligament within.

SCROBICULARIA.

18. S. PIPERITA, _Gmel._--Generic syn.: _Mya_, _Venus_, _Trigonella_, _Mactra_, _Lutraria_, _Listera_.--Specific syn.: _hispanica_, _borealis_, _plana_, _gaditana_, _Listeri_, _compressa_.--Scarborough, Southend, Swansea, Cork, Clyde, C. Broad, compressed.

DONAX.

19. D. ANATINUS, _Lamk._--_D. trunculus_, Linn.?, _Cuneus vittatus_, _D. ruber_ (young).--Brit. co. generally, sandy shores, C. Broad; margin crenulated.

20. D. POLITUS, _Poci._--(_Tellina_) _D._ and _Capsa complanata_.--S. Devon, Bantry Bay, etc., Mr. Smooth; inner edge not crenated.

MACTRA. Lives on sandy beaches.

21. M. STULTORUM, _Linn._--(_Cardium_) _Tellina radiata_, _Trigonella r._, _M. cinerea_, _M. magna_.--British co. generally, C.

22. M. ELLIPTICA, _Brown._--British co. generally, C. Oval.

23. M. SUBTRUNCATA, _Costa._--_M. lactea_, _M. triangula_, _M. crassatella_.--Brit. co. generally, C. Obliquely cuneiform.

24. M. HELVACEA, _Chemn._--_M. glauca_, _M. neapolitana_.--Odd valves found dead in Cornwall, R. Large, obliquely oval.

25. M. SOLIDA, _Linn._--_Trigonella zonaria_ and _gallina_.--Brit. co. generally, C. Trigonal, thick.

26. M. TRUNCATA, _Mont._--Forth, Cork, Cornwall, etc., C. Trigonal, deep, thick.

PLATE IV.

LUTRARIA. Inhabits mud.

Fig.

1. L. INTERMEDIA?, _Sowb._--Perhaps only the young of _L. elliptica_.

2. L. ELLIPTICA, _Lamk._--_Mactra lutraria_, Linn.--Scarborough, Torbay, Dublin, Forth, Lerwick, etc., C. Broad, oval.

3. L. OBLONGA, _Chemn._--(_Mya_) _L. solenoides_, _L. hians_, _Mactra hians_, _Chama magna_.--Cornwall, Devon, etc., Mc. Arched, narrow.

TAPES. Burrows in mud and stone.

4, 5. T. PULLASTRA, _Wood._--_Venus pullastra_, _V. perforans_ (var. f. 4), _Venerupis nucleus_, _Pullastra vulgaris_, etc.--Plymouth, Scarborough, Swansea, Forth, etc., C.

6. T. DECUSSATA, _Linn._--(_Venus_) _V. litterata_, _V. florida_, _Venerupis_ and _Pullastra d._--S. Devon, Weymouth, Tenby, etc., Mc. Oblong, coarsely decussated.

7. T. AUREA, _Gmel._--(_Venus_) _V. nebulosa_, _V. ænea_, _V. nitens_, _V. sinuata_, _Pullastra a._--Cornwall, Sussex, Bantry Bay, Loch Ryan, Mc. Yellow within.

8. T. VIRGINEA, _Linn._--(_Venus_) _V. rhomboides_, _V. sarniensis_, _V. virago_, _Cuneus fasciatus_.--Various British loc., C. Pink within.

LUCINOPSIS, _Forbes_ and _Hanley_. Sandy ground.

9. L. UNDATA, _Pennant._--(_Venus_) _V. sinuosa_, _V. incorrupta_, _Lucina undata_.--Exm., Scarborough, Man, etc., 5 to 80 fathoms, M.R. Orbicular, flexuous at side.

ARTEMIS.

10. A. EXOLETA, _Linn._--(_Venus_) _Cytherea e._, _Pectunculus capillaceus_.--Sandy ground, on Brit. co. generally, low-water to 80 fath., C. Compressed; striæ coarse.

11. A. LINCTA, _Pult._--(_Venus_) _V. sinuata_, _Cytherea sinuata_.--Various Brit, loc., C. Dorsal edge sloping; striæ fine.

VENUS.

12. V. CASINA, _Linn._--_V. reflexa_, _V. lactea_, _V. discina_.--Northumberland, S. Devon, Man, Bantry, Skye, etc., Mc. Concentrically laminated.

13. V. VERRUCOSA, _Linn._--_V. erycina_, _V. cancellata_, etc.--Devon, Cornwall, Channel Isls., etc., C. Ventricose, warted.

14. V. FASCIATA, _Donov._--Various southern Brit, loc., C. Round, with thick ribs.

15. V. OVATA, _Pennant._--Brit. co. generally, C. Oval, radiately ribbed.

16. V. STRIATA, _Donov._--_V. gallina_, _V. Pennantii_, _V. rugosa_.--Brit. co. generally. Shores and deep water, C.

ASTARTE.

17. A. TRIANGULARIS, _Mont._--_Mactra_ and _Goodallia_, _minutissima_ and _triangularis_.--Northern parts of Britain, 15 to 20 fathoms, C. Minute, triangular.

18. A. ELLIPTICA, _Brown._--_Crassina e._, _Crassina ovata_, and _C. sulcata_. Scotland, 5 to 10 fath., mud, M. C. Oblong, smooth near the margin.

19. A. SULCATA, _Costa._--(_Pectunculus_) _V. scotica_ and _Damnoniensis_, _Crassina sulcata_, etc.--Devon, Cornwall, Bantry, etc., C. Thickly ribbed.

20. A. COMPRESSA, _Mont._--(_Venus_) _Venus and Crassina Montagui_, _Cyprina comp._--Scarborough, Northumbria, Bantry Bay, Firth of Forth, 7 to 40 fath., M. C.

21. A. CREBRICOSTATA, _Forbes._--Zetland and Skye (dead), R. Ribs more numerous than in _A. sulcata_.

22. A. ARCTICA, _Gray._--(_Crassina_) _Venus borealis_, _Astarte compressa_.--Aberdeen, Zetland, St. Andrew's bay, etc., Rr. Lenticular, not ribbed.

CYTHEREA.

23. C. CHIONE, _Linn._--(_Venus._)--Plymouth, S. Devon, Falmouth, Carnarvon, 12 to 20 fath., Mr.

PLATE V.

CYPRINA.

Fig.

1. C. ISLANDICA, _Linn._ (_Venus._)--_C. vulgaris_, _V. mercenaria_.--Brit. co. generally, most abundant north, 5 to 80 fath. Oval, with thick epidermis.

CIRCE.

2. C. MINIMA, _Mont._ (_Venus._)--Gen. _Cyprina_ and _Cytherea triangularis_, _apicialis_, _Cyrillii_, _minuta_.--Guernsey, Cornwall, Milford Haven, Clyde, Bantry Bay, etc., 10 to 50 fath., C.

ISOCARDIA.

3. I. COR, _Linn._ (_Chama._)--_I. hibernica_, _Cardita cor._--Dublin, Skye, etc., Mc. Heart-shaped, beaks coiled.

CARDIUM, or _Cockle_.

4. C. PYGMÆUM, _Donovan._--_C. exiguum._--Herne, Sark, Weymouth, Zetland, Bantry Bay, 5 to 50 fath., Mc. Hinder side large, angular.

5. C. PAPILLOSUM, _Poli._--Guernsey, St. Martin's Port, _Jeffreys_, R. Rather rounded, equally ribbed and grained.

6. C. PUNCTATUM, _Broc._, C. NODOSUM, _Turt._--_C. scabrum_, Ph.--Exmouth, Falmouth, Galloway, etc., Mc. Angular behind.

7. C. FASCIATUM, _Mont._--_C. elongatum_, _C. ovale_, _C. parvum_, _C. rubrum_ (young).--Various Brit. loc., Mr.

8. C. SUECICUM, _Loven._--_C. Swediense_, Reeve, _C. Loveni_, Thompson.--Down, Oban, Zetland, 30 to 70 fath., Rr. Oval, equally ribbed.

9. C. ACULEATUM, _Linn._--_C. ciliare_ and _parvum_ (young).--S. Devon, Mc. Thin, oblique, with thorn-like tubercles; interstices of ribs smooth.

10. C. RUSTICUM, _Linn._--_C. tuberculatum_, Linn.?--Paignton, Torbay, Velvet Strand, Dublin co., Mc. Thick, not oblique, coarsely wrinkled.

11. C. ECHINATUM, _Linn._--_C. mucronatum_, _C. spinosum_.--Brit. co. generally, mud and sand, 7 to 80 fath. Oblique, wrinkled; hinder tubercles sharp.

12. C. EDULE, _Linn._--_C. vulgare_, _C. zonatum_, _C. obliquum_, _C. crenulatum_, _C. rusticum_.--Brit. co. generally. Common eatable, Cockle.

13. C. NORVEGICUM, _Spengler._--_C. lævigatum_, _C. serratum_, _C. oblongum_, _C. Pennantii_.--Brit. co. generally. Sand and gravel, 15 to 80 fath. Smooth, variegated when young.

LUCINA.

14. L. DIVARICATA, _Linn._ (_Tellina._)--_Cardium arcuatum_, _L. arcuata_, _commutata_.--Near Falmouth, 20 fath., Rr. Rounded, with diverging ribs.

15. L. FLEXUOSA, _Mont._ (_Tellina._)--_Venus sinuosa_, _Amphidesma flexuosa_, _L. sinuata_; gen. _Cryptodon_, _Axinus_, and _Ptychina_.--Clyde, Bantry, Anglesea, etc., 7 to 80 fath., Mc. Thin, with a fold behind.

16. L. BOREALIS, _Linn._ (_Venus._)--_Tellina radula_, _Lucina r._, _L. alba_.--Many Brit. loc., 1 to 90 fath., C. Lenticular, concentrically laminated.

17. L. LEUCOMA, _Turt._--_L. lactea_, not Linn., _Loripes lactea_.--Torbay, Scarborough, Bantry Bay, etc., low-water to 80 fath., C. Round, smooth.

18. L. SPINIFERA, _Mont._ (_Venus._)--_Myrtea s._, _L. hiatelloides_.--Dartmouth, Plymouth, Hebrides, etc., 8 to 100 fath., M. R. Oval; dorsal margin spinose.

DIPLODONTA, _Mont._

19. T. ROTUNDATA, _Mont._ (_Tellina._)--_T. undata_, _Lucina r._, _D. dilatata_.--Dorset, Devon, Tenby, Bantry Bay, etc., 7 to 25 fath., R.

CLAUSINA, _Jeffreys._

20. C. FERRUGINOSA, _Forbes_, (_Kellia._)--Skye, Loch Fyne, etc., 30 to 100 fath., C. Concentrically ribbed, minute, oval.

21. C. CROULINENSIS, _Jeffreys._--Croulin Island, Shellands, R. Suborbicular.

22. C. ABYSSLICOLA, _Jeffreys._--Not ribbed, R.

PLATE VI.

MONTACUTA.

Fig.

1. M. FERRUGINOSA, _Mont._ (_Mya._)--_M. oblonga_, _M. glabra_, _Tellimya elliptica_, _Erycina f._--S. Devon, Scarborough, Tenby, Cape Clear, etc., Mr. Wedge-shaped, long.

2. M. BIDENTATA, _Mont._ (_Mya._)--_Erycina_, _Petricola_, and _Tellimya b._--Newcastle, Weymouth, Dublin, etc. Burrows in dead shells, Mr. Short, subquadrate.

3. M. SUBSTRIATA, _Mont._ (_Mya._)--_Erycina_ and _Tellimya s._--Devon, Tenby, Durham, Zetland, Bantry Bay, etc., on spines of _Spatangus_, deep water, C. Minute, with diverging striæ.

TURTONIA.

4. T. MINUTA, _O. Fabr._ (_Venus._)--_Mya purpurea_, etc.--Scarborough, Tenby, Cork, Oban, etc., C.

KELLIA.

5. K. SUBORBICULARIS, _Mont._ (_Mya._)--_Bornia inflata_, _Tellina_ and _Tellimya s._--Anglesea, Portland, Zetland, etc., low-water to 60 fath., Mr.

6. K. LACTEA, _Brown_, (_Tellimya._)--Brit. co. generally. More oblong than _K. sub._

7, 8. K. RUBRA, _Mont._ (_Cardium._)--_Poronia r._, etc.--Numerous localities; littoral, C.

LEPTON.

9. L. SQUAMOSUM, _Mont._--_Solen_ and _Lutraria s._--Salcombe Bay, Tenby, Cork, etc., R. Flat, subquadrate.

10. L. NITIDUM, _Turt._ (_Kellia._)--Torbay, Skye, R. Less square and flat than _L. squamosum_.

11. L. CONVEXUM, _Alder._--Bantry Bay, Rr. Convex, granulated.

12. L. CLARKIÆ, _Clark._--Exmouth, Plymouth, Zetland, Rr. Minute, oval, smooth.

13. L. SULCATULUM, _Jeffr._--Annals, Feb. 1859. Guernsey, Mc. Concentrically wrinkled.

GALEOMMA. Adheres to rocks by byssus.

14, 15. G. TURTONI, _Sowb._--Channel Islands, and Exmouth. Oblong, gaping.

CYCLAS. Inhabits fresh-water.

16. C. CORNEA, _Linn._ (_Tellina._)--_Sphærium c._, Scopoli, _C. rivalis_, etc.--Ponds and ditches everywhere. Equilateral, subquadrate.

17. C. PISIDIOIDES, _Gray._--_C. cornea_, var., Brit. Moll.--Ditches and ponds, C. Oblique, and light coloured.

18. C. RIVICOLA, _Leach._--_Cardium nux_, etc.--Thames, etc. Large, oval, wrinkled.

19. C. CALICULATA, _Drap._-_C. lacustris_, etc.--Newcastle, Bristol, etc., Mr. With a ridge at the apex.

20. C. LACUSTRIS, _Drap._--_pallida_, Gray.--Regent's Park, etc., Mr. Oval, light.

PISIDIUM. Inhabits fresh-water.

21. P. OBTUSALE, _Pfeiffer._--_P. pusillum_, var.?

22. P. PUSILLUM, _Turton_, (_Tellina._)--_Cyclas fontinalis_ and _gibba_.--In marshes and ponds at various places, C. Includes _P. obtustale_?

23. P. AMNICUM, _Müller_, (_Tellina._)--_T. rivalis_, _Cyclas palustris_, _C. obliqua_.--British rivers, etc., generally. _C. obliqua_ ribbed.

24. P. NITIDUM, _Jennyns._--Battersea, Swansea, etc., C. Thick, dark, blunt.

25. P. HENSLOWIANUM, _Sheppard_, (_Tellina._)--_Cyclas appendiculata_, _P. acutum_.--Cambridge, Swansea, etc., R. With a projection on the umbones.

26. P. PULCHELLUM, _Jennyns._--_Cyclas fontinalis_, etc.--Various localities, C. Ridged.

27. P. CINEREUM, _Alder._--_Cyclas c._--Various localities, Mc. Smooth.

28. P. ROSEUM, _Scholtz._--Various loc., with _P. pulchellum_ and _P. nitidum_ M. C. Subquadrate; animal pink.

PLATE VII.

UNIO. Fresh-water Mussel with hinge-teeth.

Fig.

1. U. MARGARITIFERUS, _Linn._ (_Mya._)--_Alasmodon m._, _A. arcuata_, _U. elongata_, _U. sinuata_.--R. Conway; rivers in Cumberland, Wales, Ireland, etc., Mc. Long, thick, arched.

2. U. PICTORUM, _Linn._ (_Mya._)--_U. ovalis_, _U. rostrata_, _U. limosus_, _U. Deshayesii_, etc.--Various British rivers, C. Long, oval, not wedge-shaped behind.

3. U. TUMIDUS, _Retz._--_Mya_ and _Unio ovalis_, _M. depressa_, _M. ovata_, _Myscei o._, _M. solida_.--Thames, and various British rivers, C. More solid, deep, and wedge-shaped than _U. pictorum_.

ANODONTA. Fresh-water Mussel, without teeth.

4. A. CYGNEA, _Linn._ (_Mytilus._)--_M. anatinus_, _M. stagnalis_, _M. paludosa_, _Symphonota cy._--Britain and Europe generally, in rivers and canals, C.

DREISSINA, _Beneden._

5. D. POLYMORPHA, _Pallas_, (_Mytilus._)--London Docks, Edinburgh Canal, C.

MODIOLA, _Lamarck._

6. M. MODIOLUS, _Linn._ (_Mytilus._)--_M. umbilicatus_, _M. curtus_, _M. vulgaris_.--British coasts generally, C. Large, brown, not rayed.

7. M. OVALIS?, _Sowb._--_M. tulipa_ (_radiata_), var., Brit. Moll., now named provisionally. Less tumid, and with longer and more gradually sloped dorsal line than _M. radiata_, Rr.

8. M. RADIATA, _Hanley_, _Brit. Marine Conch._--_M. tulipa_, Brit. Moll., Mc. Tumid, radiated.

9. M. BARBATA, _Linn._ (_Mytilus._)--_M. Gibbsii._--Jersey, Torbay, Milford Haven, Youghal, R. as Brit. Barbs of epidermis serrated.

10. M. PHASEOLINA, _Philippi._--Guernsey, Falmouth, Scotland, Mc. Small barbs of epidermis not serrated.

11. M. CUPREA, _Jeffreys_, _Ann. Nat. Hist. Jan. 1859_.--In the stomach of a bird shot at Scarborough, Rr. Minute, rhomboidal, smooth.

CRENELLA, _Brown._

12. C. NIGRA, _Gray_, (_Modiola._)--_Mytilus_ and _Modiola discrepans_, _depressa_, _compressa_, _discors_.--Scotland, R. Broad and compressed behind.

13. C. DISCORS, _Linn._ (_Mytilus._)--_Modiola d._ and _discrepans_.--Brit. co. generally, among seaweeds, C. Wedge-shaped and lobed.

14. C. MARMORATA, _Forbes._--_Mytilus_ and _Mediola discors_, _discrepans_, and _tumida_.--Brit. co. generally, Cc. Rhomboidal, marbled.

15. C. COSTULATA, _Risso._--Exmouth, Cornwall, Swansea, Herm. Wedge-shaped, marbled, strongly-ribbed.

16. C. RHOMBEA, _Berkley_, (_Modiola._)--_M. Prideauxiana._--Guernsey, Torbay, Penzance, etc.; coralline, R.

17. C. DECUSSATA, _Montagu_, (_Mytilus._)--_C._ and _Modiola elliptica_, _cicercula_, and _faba_.--Scarborough, and a few northern localities, 5 to 50 fath., Mc.; Norway, etc. Subquadrate, decussated, minute.

MYTILUS, _Linn._

18. M. EDULIS, _Linn._--_M. vulgaris._--Brit. co. generally, Cc. Byssal margin swelled.

19. M. UNGULATUS, _Linn. Syst. Nat._--_M. edulis_, var. _M. incurvatus_ (Hoof-Mussel).--Cornwall, Guernsey, etc., Mr. Byssal margin bent inwards, lower margin broad and straight.

20, 21. M. GALLOPROVINCIALIS, _Lamk._--_M. edulis_, var. _M. dilatatus_?, _M. pellucidus_? (young, f. 21), _M. subsaxatilis_?--British Channel, etc., C. Dorsal margin dilated, beak advancing.

PLATE VIII.

NUCULA, _Linn._

Fig.

1. N. NUCLEUS, _Linn._ (_Arca._)--_N. margaritacea_, _Glycimeris argentea_.--Brit. co. generally, 7 to 90 fath., C. Thick, obtuse; beaks terminal.

2. N. DECUSSATA, _Sowerby._--_N. sulcata_, _N. Polii_.--Hebrides, Loch Fyne, Dublin Bay, 30 to 50 fath., Mr. Large, striated; beak not terminal.

3. N. RADIATA, _Hanley._--_N._ and _Arca nucleus_ and _radiata_.--Torbay, Milford Haven, Arran, etc., 10 to 70 fath., Mc. Prolonged anteriorly, rayed.

4. N. NITIDA, _Sowerby._--_N. nucleus_, var.--Numerous British loc., 1 to 35 fath., C. Shining, ends rather pointed.

5. N. TENUIS, _Montagu_, (_Arca._)--North British co., 40 to 100 fath., sand, C. Thin, inner edge not crenated; beak terminal.

LEDA, _Schum._ Beaked behind.

6. L. CAUDATA, _Donovan_, (_Arca._)--_Arca_ and _Nucula minuta_ and _rostrata_.--North co., C.; south co., R. 10 fath. to deep water. Ridged.

7. L. PYGMÆA, _Munster_, (_Nucula._)--_N._ and _L. tenuis_, _gibbosa_, and _lenticula_.--Skye, Hebrides, Croulin Isl., 25 to 50 fath. Minute, smooth. Size (omitted) one-fifth of an inch.

ARCA, _Linnæus._

8, 9. A. LACTEA, _Linn._--_A. barbata_, _A. Modiolus_, _A. crinita_, _A. perforans_, _A. Gaimardii_, var. f. 8; _A. Quoyi_, var. f. 9.--Penzance, Ilfracombe, Bantry Bay, Guernsey, etc. Adhering to shells and stones, 15 to 20 fath., C. Beaks approaching, radiately striated.

10. A. TETRAGONA, _Poli._--_A. Noæ_ and _imbricata_.--Many Brit, loc., C. (12 to 50 fath.). Broad area between beaks.

11. A. RARIDENTATA, _S. Wood._--_A. pectunculoides._--Skye, Hebrides, etc., Scot. Cape Clear, 40 to 60 fath., Mr. Minute, teeth few.

12. A. NODULOSA, _Ph._--E. Zetland, Shetland Isls., Rr.

PECTUNCULUS.

13. P. GLYCIMERIS, _Linn._ (_Arca._)--_A._ and _P._ and _Glycimeris pilosa_, _orbicularis_, _undata_, and _marmorata_.--Brit. co. generally, 15 to 60 fath., C.

LIMOPSIS.

14. L. PELLUCIDA, _Jeffreys_, _Ann. Nat. Hist. Jan. 59_.--Dredged in sand at Guernsey, Rr.

AVICULA.

15. A. TARENTINA, _Lamk._--_Mytilus_ and _Avicula hirundo_, etc.--Bantry Bay, Devon, etc., R.

PINNA.

16. P. PECTINATA, _Linn._--_P. fragilis_, _muricata_, _ingens_, _lævis_, _papyracea_, _rotundata_, _elegans_.--Dorset, Milford Haven, Hebrides, Cape Clear; deep water, Mc.

OSTREA.

17. O. EDULIS, _Linn._--_O. vulgare_, etc.--Various natural and artificial beds, in England, Scotland, and Ireland. The common Oyster.

ANOMIA.

18. A. EPHIPPIUM, _Linn._--_A. electrica_, _A. squamula_, _cepa_, etc.--Brit. co. generally, 1 to 30 fath., C. Pearly and irregular; beak marginal, curved.

19. A. ACULEATA, _Müller._--_A. striolata._--Brit. co. generally, Mc. Small, with spinous sculpture.

20. A. STRIATA, _Lovén._--Hebrides, R. Rayed, striated, with apex not marginal.

21. A. PATELLIFORMIS, _Linn._--_A. undulata._--Cape Clear, etc., 1 to 50 fath., Mr. Flat, ribbed.

LIMA.

22. L. SUBAURICULATA, _Montagu_, (_Pecten._)--_L. nivea_, _sulcata_, etc.--Plymouth, Man, Zetland, Belfast, etc., Mr. Nearly straight.

23. L. HIANS, _Gmel._ (_Vitræa._)--_L. tenera_, _fragilis_, _aperta_, etc.--Channel Isls., Penzance, Oban, Belfast, etc., Mc. Oblique, gaping at sides.

24. L. LOSCOMBII, _Sowerby._--_Pecten_ and _Ostrea_ and _Lima fragilis_ and _bullata_.--Many Brit. loc., 10 to 50 fath., Mc. Oblique, closed at sides.

PLATE IX.

PECTEN. Free, except 1.

Fig.

1. P. PUSIO, _Pennant_, (_Ostrea._)--_P._, _O._, and _Hinnites distortus_ and _sinuosus_.--Brit. co. generally, 15 to 90 fath., C. Irregular, attached to stones, etc.

2, 3. P. VARIUS, _Linn._ (_Ostrea._)--_P. monotis._--Brit. co. generally, 3 to 35 fath.; C. Vertically elongate; auricles very unequal.

4. P. NIVEUS, _Macgillivray._--Scotland, R. (15 fath.) Ribs more numerous than _P. varius_; white.

5, 6, 7. P. OPERCULARIS, _Linn._ (_Ostrea._)--_O._, and _P. subrufus_, _pictus_, _lineatus_ (var. f. 6), and _sanguinea_.--Brit. co. generally, 5 to 100 fath., C. As broad as long; ribs rounded.

8. P. AUDOUINII, _Payraudeau._--_P. opercularis_, var., B. Moll.--Ribs angular and squamose.

9, 10. P. DANICUS, _Chemn._--_P._ and _O. pes-felis_, _glaber_, _triradiata_, _adspersus_, _septemradiata_, etc.--Several Scotch localities, 25 to 90 fath., Mc. Very variable, extreme vars. f. 9, 10. Auricles more equal than _P. tigrinus_.

11, 12. P. TIGRINUS, _Müller._--_P. obsoletus_, _domesticus_, _lævis_, _parvus_, etc.--Brit. co. generally, 12 to 60 fath., C. Variable; one auricle minute, the other large and ribbed.

13. P. MAXIMUS, _Linn._ (_Ostrea._)--_P. vulgaris._--Brit. co. generally, 3 to 40 fath. The common eatable Scallop. Valves unequal.

14. P. SIMILIS, _Laskey._--_O._ and _P. tumidus_.--Fr. Forth, Isl. Man, Lerwick, Cape Clear, etc., Mc. Minute, smooth, with undulating marks.

15. P. STRIATUS, _Müller._--_P. aculeatus_, _fuci_, etc.--Scotland, C.; England, R.

16. P. FURTIVUS, _Lovén._--Zetland, Guernsey, etc., 40 to 50 fath., Mr. More rounded, and with auricles less broadly based than _P. striatus_.

HIPPOTHYRIS. Fixed by byssus.

17. H. PSITTACEA, _Gmel._ (_Anomia._)--_A. rostrum-psittaci_, Chem.; _Terebratula psittacea_.--Northumberland, Fr. Forth; deep water, Rr. as Brit. "The Parrot's-beak Anomia."

TEREBRATULA. Fixed by byssus.

18. T. CRANIUM, _Müller._--_Anomia c._, and _T. vitrea_.--Zetland; deep water, unique as Brit. Smooth, oval.

19. T. CAPSULA, _Jeffreys_, _Ann. Nat. Hist._, _Jan. 1859_.--Belfast Bay, R. Minute, punctured.

ARGIOPE, or MEGATHYRIS.

20. T. CAPUT-SERPENTIS, _Linn._ (_Anomia._)--_A._ and _T. retusa_, _pubescens_, _costata_, and _aurita_.--Oban, Skye, etc., 20 to 50 fath., Mr.

21. A. CISTELLULA, _S. Wood._ (_Terebratula._)--_A. seminulum_?, T.

22. A. DECOLLATA, _Chemn._--_A. detruncata._--Guernsey, R.

23. A. SEMINULUM, _Philippi._--Croulin, near Skye, _Jeffreys_.

CRANIA.

24. C. ANOMALA, _Müller._ (_Patella._)--_Pat. Anomia_, _Discina_, and _Criopus distorta_, _ostreoides_, _personata_, and _rostrata_.--Zetland, Arran, Lerwick, Cork, Mr.

PLATE X.

HYALÆA. _Fam._ Pteropoda.

Fig.

1. H. TRISPINOSA, _Lesueur._--Once taken on floating timber, Dublin. Doubtful as British.

SPIRIALIS, or PERACLE. _Fam._ Pteropoda.

2. S. FLEMINGII, _Forbes._--_Fusus retroversus_, Fl.--Zetland, Skye, Arran, Donegal, M. C. Snail-shaped.

3. S. MACANDREI, _F. and H._--Near Mizen Head, S. Ire., Rr. Turreted.

4. S. JEFFREYSII, _F. and H._--Brit. Channel, Rr. Discoid.

CHITON. Sedentary on rocks.

5. C. FASCICULARIS, _Linn._--Brit co. generally, Mc. Tufted margin, small, granules large.

6. C. GRACILIS, _Jeffr._ _Ann. Nat. Hist._, _Jan. 1859_.--Weymouth. Narrow; granules very small; two postero-terminal tufts.

7. C. DISCREPANS, _Brown._--_crinitus_, Pennant?--Tenby, Guernsey, C. Tufted margin, large: granules very small.

8. C. HANLEYI, _Bean._--Scarborough, Skye, W. Ireland, R. Spinose margin.

9, 10. C. MARMOREUS, _O. Fabr._--_C. latus_, Lowe, _C. lævigatus_, _ruber_, and _pictus_.--Scarborough, Forth, Skye, Zetland, W. Ire., R. Margin smooth.

11. C. LÆVIS, _Pennant._--_C. marginatus_, Pult., _C. Achatina_, Brown.--Dorset, Devon; Brit. co. generally, but rare. Dorsally elevated; margin reticulated.

12. C. RUBER, _Linn._--Brit, seas generally, Mr. Valves smooth; margin coriaceous.

13. C. CINEREUS, _Linn._--_C. marginatus_, Penn.?--Brit. co. generally, C. Valves carinated; margin and valves granulated.

14. C. ALBUS, _Linn._--_C. asselloides_, Lowe.--Northern coasts, R. Marginal granules scaly and large; dorsal gr. smaller than _C. cinereus_.

15, 16. C. ASSELUS, _Chemn._--_C. minimus_, _Cinereus albus_.--Brit. co. generally, C. Broad, granules on valves beaded.

17. C. CANCELLATUS, _Sowerby._--_C. albus_, Pult.--Devon, Guernsey, Isl. Man, Oban, Zetland, Loch Carron, R. Narrow, back elevated, else like _C. assellus_.

PATELLA. (Limpet.) Sedentary.

18. P. VULGATA, _Linn._--Brit, generally, Cc. Ribs not toothed.

19. P. ATHLETICA, _Bean._--Devon, Northumberland, etc., Cc. Ribs toothed.

20. P. PELLUCIDA, _Linn._--_P. lævis_, _cærulea_, _Acmæa pel_.--British co. generally, C. smooth.

21. ---- var. _lævis_, Penn.

ACMÆA, or LOTTIA.

22. A. TESTUDINALIS, _Müller._--_P. Clealandi._--North Ire., C. Oval, with tortoise-shell markings.

23. A. VIRGINEA, _Müller._--_P. parva_, _pulchella_.--Brit. co. generally, Mc. Pale, pink-rayed, shallow.

PILIDIUM, or TECTURA.

24. P. FULVUM, _Müller._--_P. Forbesii._--Clyde, Cork, Zetland, etc., R.

PROPILIDIUM.

25. P. ANCYLOIDE, _Forbes._--Lamlash, Ayrshire, etc., R.

DENTALIUM, _Linn._

26. D. ENTALIS, _Linn._--Brit. co. generally, C. Smooth, small end notched.

27. D. TARENTINUM, _Lamk._--_D. vulgare_, _striatum_, _labiatum_, _politum_, _læve_.--South coasts, C. Striated and entire at small end.

PILEOPSIS, or CAPULUS.

28. P. HUNGARICUS, _Linn._--Fool's-cap Limpet.--S. Devon, and Br. co. generally, C.

CALYPTRÆA, _Linn._

29. C. SINENSIS, _Linn._ (_Patella._)--_C. chinensis_, _albida_, _lævigata_.--S. Brit., and Chan. Isls., R. With oblique septum.

PLATE XI.

FISSURELLA.

Fig.

1. F. RETICULATA, _Donov._ (_Patella._)--_P._ and _F. Græca_, _apertura_ (young), _cancellata_, _europæa_.--Hebrides, Thanet, Devon, Ireland. On shells, etc., 1 to 15 fath., C.

2. F. COSTARIA, _Deshayes._--Guernsey, R. More fine and numerous ribs than _F. reticulata_.

PUNCTURELLA.

3. P. NOACHINA, _Linn._ (_Patella._)--_Cemoria Flemingii_, _Fissurella N._, _Rimula Flemingii_, etc.--Scotland and Northumberland, 20 to 100 fath., R. With slit under apex.

EMARGINULA.

4. E. RETICULATA, _Sowerby._--_Patella fissura_, etc.--Brit. co. generally, C. Conical, with slit in margin.

5. E. ROSEA, _Bell._--_E. pileolus_, _conica_, _capuliformis_, etc.--Channel Isls., Exmouth, Cornwall, etc., 7 to 25 fath., Mc. Curved, coarsely cancellated. Red within.

6. E. CRASSA, _Sowerby._--Loch Fyne, Oban and Belfast, 20 to 25 fath., Rr. Large, not cancellated.

HALIOTIS, or "Ear-shell."

7. H. TUBERCULATA, _Leim._--_H. vulgaris_, Channel Isls., Cc.

TROCHUS.

8. T. ZIZYPHINUS, _Linn._-_-C. conulus_, _C. discrepans_, _C. Lyonsii_ (white, ribbed var.), etc. Brit. co. generally, low-water to 50 fath., C.

9. T. CONULUS, _Linn._--Lincolnshire, Rr. More simply conical than the most extreme forms of _T. zizyphinus_.

10. T. ALABASTRUM, _Beck._--_T. formosus_.--Zetland, Lerwick, etc., 45 to 80 fath., R. White, with deep, plain, and beaded ridges.

11. T. MILLEGRANUS, _Philippi._--_T. Clealandi_, _T. Martini_.--Brit. co. generally, 15 to 90 fath., Mr. Granulated, whorls with prominent margin.

12. T. GRANULATUS, _Born._--_T. papillosus_, _T. fragilis_.--Channel Isls., Weymouth, Dublin, etc., R. Like 8, but grained.

13. T. STRIATUS, _Linn._--_T. parvus_, etc.--S. Brit., C. More finely ribbed than _T. exiguus_.

14. T. EXIGUUS, _Pult._--_T. exasperatus_, _minutus_, etc. S. co., C.

15. T. MONTAGUI, _Gray._--_T. striatus_, Forbes.--Scarborough, Exmouth, Cape Clear, etc., C. Elevated, whorls tumid.

16. T. TUMIDUS, _Mont._--_T. patholatus_, _Rackettii_, etc. Brit. co. generally, C. Short, whorls tumid, umbilicated.

17. T. CINEREUS, _Linn._--_T. lineatus_, _T. perforatus_, etc.--Brit. co. generally, C. Littoral, small umbilicus.

18. T. UMBILICATUS, _Mont._--_T. cinerarius_, etc.--Guernsey, S. and W. Brit. co., C. Littoral, umbilicus large.

19. T. MAJUS, _Linn._--_T. tuberculatus._--Brit. co. generally; littoral, C. Broad, tuberculated. Large umbilicus.

20. T. LINEATUS, _Costa._--_T. crassus_, etc.--Channel Isls., Devon. W. Ire., Mc. Smooth, imperforate.

MARGARITA, or TROCHUS.

21. M. UNDULATUS, _Sowerby._--_Turbo carneus_, _M. striata_, etc.--Scotland, 5 to 50 fath., Mc. Striated and undulated.

22. M. HELICINUS, _Fabricius._--_Turbo_ and _Trochus neritoideus_, _margarita_, _M. vulgaris_, etc.--Many Brit. loc.; littoral, C.

23. M. PUSILLUS, _Jeffreys._--Lerwick, R., 10 to 40 fath. Minute, white, depressed.

24. M. EXILIS, _Phil._--_Skenea Cutleriana._--Guernsey, Skye, etc., R. Globose, striated.

ADEORBIS.

25. A. SUBCARINATA, _Mont._--(_Helix_) _Trochus rugosus_, _Cingula subc._, etc.--S. Brit, co., Mr. Depressed, keeled.

SCISSURELLA.

26. S. CRISPATA, _Flem._--Zetland, etc., in sand, Mc.

PHASIANELLA.

27. P. PULLUS, _Linn._ (_Turbo._)--_T. pictus_, _Cingula p._, etc.--Brit. co. generally, C.

PLATE XII.

IANTHINA. Floats on ocean.

Fig.

1. I. COMMUNIS, _Lamk._--_Helix Ianthina_, _I. fragilis_, etc.--Cornwall, Bristol, etc.; oceanic, C. Sides depressed.

2. I. BRITANNICA, _Leech._ _Reeve._--Ireland, Cornwall, etc., Mr. Darkly coloured, not compressed.

3. I. PALLIDA, _Harvey._--_I. patula._--Clare, Rr. as Brit.

4. I. EXIGUA, _Lamk._--Cornwall, Clare, etc., Mr.

NERITINA. In rivers.

5. N. FLUVIATILIS, _Linn._--_N. fontinalis._--Thames, Trent, Humber, etc., Scotch lakes, Cc.

BITHINIA. In ponds.

6. B. LEACHII, _Shepp._ (_Turbo._)--_B. ventricosus_, _Paludina acuta_, _similis_, etc.--Rivers S. Brit., Mr. Narrow, with rounded whorls.

7. B. TENTACULATA, _Linn._ (_Helix._)--_T. nucleus_, _Paludina impura_, etc.--Fresh-water, throughout Brit. Oval.

PALUDINA. In ponds.

8. P. LISTERI, _Forbes and Hanley._--_Helix vivipara_, etc.--Lakes and ponds generally, Mc. Whorls more separate, umbilicus larger than _P. vivipara_.

9. P. VIVIPARA, _Linn._--_Pal. achatina_, etc.--Thames, etc., C.

VALVATA. In ponds.

10. V. PISCINALIS, _Müller._--_Nerita_, _Turbo_, _Cyclostoma fontinalis_, _obtusa_, _thermalis_, etc.--Fresh-water, C. Subglobose.

11. V. CRISTATA, _Müller._--_V. planorbis_, etc.--Many loc., Mc. Orbicular.

LITTORINA. On the sea-shore.

12, 13. L. RUDIS, _Donov._ (_Turbo._)--_L. littoreus_, etc., _L. nigro-lineatus_ (var. f. 13).--British shores generally, Cc.

14, 15. L. LITTOREA, _Linn._ (_Turbo._)--_L. vulgaris_, etc.--British shores generally. The common eatable Winkle.

16, 17. L. TENEBROSA, _Mont._ (_Turbo_).--British shores generally, C. Not thickened at bottom of mouth like _L. rudis_.

18. L. PATULA, _Jeffreys._--_L. labiata_, _L. jugosa_, etc.--Common on our shores.

19. L. SAXATILIS, _Johnston._--_L. neglecta._--Probably _L. patula_ var.?

20, 21. L. LITTORALIS, _Linn._ (_Turbo._)--_T. neritoides_, _T. ustulatus_, etc,--Brit. co. generally. Depressed above.

22. L. FABALIS, _Turt._--_L. Beanii._--Young of _L. littoralis_?

23. L. NERITOIDES, _Linn._ (_Turbo._)--_T. petræa_, _L. cærulea_, etc.--Kent, Sussex, etc., C. With white band.

24. L. PALLIATA, _Say_, (_Turbo._)--Yarmouth, Mr.

LACUNA.

25, 26. L. PUTEOLUS, _Turt._ (_Turbo._)--_Cochlea_, _Helix_, and _Nerita parva_, _fasciata_, _lacuna_, _rufa_, etc.--Brit. shores, C. Globose.

27, 28. L. VINCTA, _Mont._ (_Turbo._)--_T. canalis_, _quadrifasciatus_, etc,--Brit. co. generally, C.

29. L. CRASSIOR, _Mont._ (_Turbo._)--_L. pallidus._--Numerous Brit. co. Thick, conical.

30. ---- var. ? of this rather than of _C. vincta_.

31. L. PALLIDULA, _Costa_, (_Turbo._)--Brit. co. generally, C.

32. L. PATULA.--Fry of _L. pallidula_?

PLATE XIII.

ASSIMINEA.

Fig.

1. A. GRAYANA, _Jeffreys._--_Limneus_ and _Paludina G._--Greenwich and other marshes.

2. A. LITTOREA, _Delle Chiaje_, (_Helix littorina._)--_Rissoa globularis_ and _littorea_.--On shore at Weymouth, Serk, Portland, Mr.

RISSOA, or CINGULA.

3. R. ULVÆ, _Pennant_, (_Turbo._)--_Helix_, _Cingula_, _Paludina_, and _Littorina_.--In brackish water, on British shores, C.

3*. ---- var. _subumbilicata_, R.

4. R. BARLEEI, _Jeffreys._--_R. ulvæ_ var.--Loch Carron, Skye, R.

5. R. STRIATULA, _Mont._--_R._, _Turbo_, _Cingula_, and _Littorina carinata_ and _monilis_.--Devon, Margate, Galway, Herm, etc., 0 to 7 fath., Mr.; S. Eu. Carinated.

6. R. CIMICOIDES, _Forbes._--_R. sculpta._--W. Scotland. Like _R. zetlandica_, but with outer lip crenulated; finely decussated.

7. R. ZETLANDICA, _Mont._ (_Turbo._)--_R._, _Cyclostoma_, _Cingula scalariformis_, _Cyclostrema z._--N. Scotland, 0 to 60 fath., Mc. Whorls angulated.

8. R. CRENULATA, _Michaud._--_Turbo_ and _R. cimex_ and _cancellatus_.--Falmouth, Cornwall, Skye, Galway, C. Very coarsely cancellated.

9. R. CALATHUS.--_Forbes and Hanley._--Sheerness, Whitesand Bay, 15 to 50 fath., R. Finely cancellated.

10. R. BEANII, _Hanley._--Cornwall, Plymouth, Orkney, Galway, C.; N. Eu. Striated.

11. R. ABYSSICOLA, _Forbes._--N. Scotland; deep water, R.

12. R. LACTEA, _Michaud._--_Turbo cancellatus._--Jersey and Medit., Rr. Oval, plicated and striated.

13. R. PUNCTURA, _Montagu._--_Turbo_ and _Cingula_ and _R. reticulata_.--Brit. co. generally, 10 to 20 fath.

14. R. COSTATA, _Adams._--_R._, _Turbo_, _Cingula plicata_, _costata_, and _exigua_.--South co. Brit., S. Wales, Orkneys, Ireland, Channel Isls., 0 to 25 fath., C.

15. R. STRIATA, _Mont._--_R._, _Turbo_, and _Cingula semicostata_, _minutissima_, _communis_, _gracilis_, etc.--Brit. co. generally, N. and S. Eu.; littoral C.

16, 17, 18. R. PARVA, _Costa._--_T._, _C._, and _R. sublutea_, _lactea_, _alba_, etc., _R. interrupta_ (var. f. 17), _R. Sarsii_, var. f. 18 (unique).--Brit. shores generally, C.

19. R. COSTULATA, _Alder._--_Turbo variabilis_, _R. similis_.--Devon, Channel Isls., W. Ireland, etc., C.; S. Eu.

20. R. RUFILABRUM, _Leach._--_R._ and _C. hyalina_ and _punctata_.--Devon, Belfast, etc., Mc.

21. R. LABIOSA, _Mont._ (_Helix._)--_T._, _C._, and _R. membranacea_ and _costata_.--Brit. co. generally, C.

22, 23, 24, R. INCONSPICUA, _Alder._--_R. albula_ and _supra-costata_, var. f. 23, _R. similis_, var. 24, _R. maculata_.--Brit. co. generally, C.

25. R. SEMISTRIATA, _Mont._--_T._ and _R. pulchra_ and _tristriata_.--Brit. shores generally, C.

26. R. CINGILLUS, _Mont._ (_Turbo._)--_R._, _T._, and _C. vittata_, var., _R. graphica_ and _R. rupestris_.--Brit co. generally.

27. R. VITREA, _Mont._ (_Turbo._)--_Helix glabrata_, _R. crystallina_.--Exmouth, Oban, Birterbuy, etc., Mr. Elongated, smooth.

28. R. PROXIMA, _Alder._--A rare Irish species. Elongated, striated.

PLATE XIV.

RISSOA,--_continued_.

Fig.

1. R. PULCHERRIMA, _Jeffreys._--Channel Isls., R.

2. R. SOLUTA, _Philippi._--Exmouth, Bute, Cork, etc., R. Like _R. pulch._, but with spiral striæ.

3. R. ALDERI, _Jeffreys_, _Annals, Aug. 1858_.--Skye, Rr. Larger and more conical than _R. soluta_.

4. R. FULGIDA, _Adams_, (_Helix._)--_Turbo_ and _Cingula f._--Weymouth, Arran, Cork, etc., Mr. Whorls rounded and banded.

5. R. ANATINA, _Drap._ (_Cyclostoma._)--_Paludina_ and _Littorina a._--Very rare, Greenwich marshes.

6. R. EXIMIA, _Jeffreys._--_Chemnitzia Barleei_, Clark.

7. R. VENTROSA, _Mont._ (_Turbo._)--_Cyclostoma_, _Paludina_, and _Cingula acutus_, _ventricosus_, _octona_, _stagnorum_, etc.--Marine shores and brackish-water marshes, Mc.

8. R. DENTICULATA, _Mont._ (_Turbo._)--Herm, Rr.

9. R. UNICA, (_Turbo._)--_Aclis u._, Brit. Moll., _Turritella_, _Pyramis_, and _Chemnitzia_, R.--Devon, Cork, etc., Mr.

10. R. GLABRATA, _Jeffreys._--N. sp.

11. R. CASTANEA, _Jeffreys._--N. sp.

BARLEEIA.

12. B. RUBRA, _Flem._ (_Cingula._)--_Turbo_, _C._, and _Rissoa ruber_, _unifasciatus_, _fulva_.--Herm, Tenby, Dunbar, etc., S. Eu., Mr.

JEFFREYSIA.

13. J. DIAPHANA, _Alder_, (_Rissoa._)--_R. glabra._--Dublin, Swansea, Northumberland, etc.; littoral, R.

14. J. OPALINA, _Jeffreys_, (_Rissoa._)--Channel Isls., R.

15. J. GLOBULARIS, _Jeffreys._--Skye.

16. J. GULSONÆ, _Clark_, (_Odostomia._)--_Chemnitzia G._--Sandwith, Lerwick, Weymouth, etc., Guernsey.

EUOMPHALUS.

17. E. NITIDISSIMUS, _Adams_, (_Helix._)--_Skenea_, B. Moll., _Truncatella atomus_.--Shetland to Channel Isls., Mc.

18. E. ROTA, _Forbes and Hanley_, (_Skenea._)--Donegal, rare. Like a minute Ammonite.

SKENEA.

19. S. PLANORBIS, _O. Fabr._ (_Helix._)--_Turbo_, _Sk. depressa_.--Brit. shores generally, on coastal Corallines, C. Flat, like a _Planorbis_.

20. S. DIVISA, _Flem._ (_Turbo._)--_Helix_ and _Sk. serpuloides_, _Adeorbis striatus_.--Scarborough, Weymouth, Orkney, Galway, etc., 7 to 25 fath., Mr. Striated.

21. S. COSTULATA, _Möller_, (_Margarita._)--Loch Fyne, Rr.

22. S. LÆVIS, _Philippi_, (_Delphinula._)--Newcastle-on-Tyne, Rr.

ACLIS.

23. A. ASCARIS, _Turt._ (_Turbo._)--_Turritella_, _Alvania_, and _Pyramis supranitida_ and _acutissima_.--Ireland, Tenby, Zetland, Mr.

24. A. SUPRA-NITIDA, _S. Wood_ (_Alvania._)--Tenby, Dublin, etc., Rr.

25. A. NITIDISSIMA, _Mont._ (_Turbo._)--_Turritella_, _Pyramis_, and _Chemnitzia_.--Falmouth, Burrow Isl., R.

EULIMELLA.

26. E. SCILLÆ, _Lovén_, (_Turbonilla._)--_Eulima_, _Odostomia_, _Chemnitzia_, and _Eulimella crassula_, and _Macandræi_.--N. Scotland, Croulin, etc., 20 to 90 fath., R.

27. E. ACICULA, Philippi, (_Melania._)--_E._, _Chemn._, _Odost._, and _Eulima clavula_.--Skye, Rr.

28. E. AFFINIS, _Philippi_, (_Eulima._)--_Pyramis_, _Odost._, and _E. gracilis_, _lævis_.--Skye, Torbay, R.

29. E. CLAVULA, _Lovén_ (_Turbonilla._)--_Odostomia c._--Torbay, Rr. Guernsey.

30. E. OBELISCUS, _Jeffreys_, _Ann. Nat. Hist. Jan. 1858._--Shetland.

PLATE XV.

TURRITELLA.

Fig.

1. T. CORNEA, _Lamk._--_T. communis_, var., B. M.--Cork and Zetland, Mr. Whorls less flat and less rapidly enlarged than _T. communis_. A white var. exists (_T. nivea_).

2, 3. T. COMMUNIS, _Risso._--_T. cornea_?, _T. Terebra_.--Brit. co. generally; 4 to 100 fath., Cc. Aperture rather square.

APORRHAIS.

4. A. PES-PELICANI, _Linn._ (_Strombus._)--_A. quadrifidus_, _Tritonium_, and _Rostellaria p._--Brit. co. gen.; N. and S. Eu.; 4 to 100 fath., C. Outer lip with one anterior lobe.

5. A. PES-CARBONIS, _Brongniart._--_Rostellaria_ and _A. p._, and _serressiana_.--Zetland, 70 to 100 fath., R. Outer lip with two anterior lobes.

CÆCUM.

6. C. TRACHEA, _Mont._--_Dentalium_ and _Orthocera imperforatum_, _C. annulatus_.--Devon, Weymouth, Scotland, Cork, etc., R.; S. Eu. Ringed and striated.

7. C. GLABRUM, _Mont._--_C._, _Dentalium_, and _Orthocera minutum_, and _lævissimum_.--Exmouth, Weymouth, Swansea, Lerwick, Bantry Bay. Rare, smooth.

CERITHIUM.

8. C. RETICULATUM, _Costa_, (_Strombiformis._)--_Murex_ and _Terebra r._--Brit. co. gen., 0 to 20 f., C. Narrow, and closely reticulated.

9. C. METAXA, _Delle Chiaje._--_C. angustissimum._--Guernsey, R.; S. Eu. Lengthened, white.

10. C. ADVERSUM, _Mont._ (_Murex._)--_C._, _Triphoris_, _Turbo_, and _Terebra a._, _perversus_, and _reticulatus_.--W. and S. Brit., Channel Isls., etc., 5 to 25 fath., Mr.

CERITHIOPSIS.

11. C. TUBERCULARE, _Mont._ (_Murex._)--_Cerithium_ and _Terebra t._--Brit. co. gen.; S. Eu.; 4 to 40 fath., Mc. Three rows of tubercles in the penultimate whorl.

12. C. CLARKII, _Hanley._--Exmouth, Rr. Two rows of tubercles.

13. C. NIVEA, _Jeffreys_, _Ann. Nat. Hist. 1859_.--In shell sand, Belfast, R. Rather Buccinum-shaped.

14. C. METULA, _Lovén_, (_Cerithium._)--_C. nitidum_, Forbes.--Zetland, 50 to 80 fath., R. White, with angular whorls.

15. C. PULCHELLA, _Jeffreys._--Falmouth, Plymouth, Guernsey, R. Closely whorled and cancellated.

SCALARIA.

16. S. COMMUNIS, _Lamk._--_Turbo_ and _Strombiformis clathrus_ and _clathratus_.--S. co. principally, C. Laminarian zone, S. Eu. Ridges raised; whorls separated.

17. S. GROENLANDICA, _Chemn._ (_Turbo._)--_S. planicostata_, _subulata_.--Fragments only, N. Scotland, N. Eu. Grooved between ridges.

18. S. TURTONIS, _Turton._--Scarborough, Exmouth, Cork, etc., N. and S. Eu., R. as Brit. Ridges flat.

19. S. TREVELYANA, _Leach._--N. Brit., 15 to 85 fath., Mr. Thin, with ribs narrower than _Sc. Turtonis_.

20. S. CLATHRATULA, _Mont._--S. Brit. and Channel Isls., Mr. Small, white, with thin ribs.

STYLIFER.

21. S. TURTONI, _Brod._--_Phasianella stylifera_, _Velutina s._, _S. globosus_ and _astericola_.--On spines of _Echinus sphæra_, Torbay and Berwick, R. Glassy, thin.

EULIMA.

22. E. POLITA, _Linn._ (_Helix._)--_Strombiformis_, _Turbo_, _Rissoa_, and _Phasianella p._ and _albus_, _Boscii_ and _anglica_.--Ireland, S. Brit., E. Scot., N. and S. Eu., 7 to 50 fath., Mr. Rather solid.

23. E. DISTORTA, _Deshayes._--Brit. co. gen., Mc.; 12 to 90 fath.; N. and S. Eu. Small, tortuous.

24. E. STENOSTOMA, _Jeffreys_, _Ann. Nat. Hist. 1858._--Zetland and Norway, Rr. Thin, with rapidly increasing whorls.

25. E. SUBULATA, _Donov._ (_Turbo._)--_Strombiformis_, _Helix_, and _Melania s._ and _glaber_, _trifasciatus_, _Donovani_, and _lineata_.--S. and W. Brit., Ire., Zetland, Medit., 10 to 80 fath., Mr. Whorls deep, banded.

26. E. BILINEATA, _Alder._--Or _E. subulata_, var.--Northumberland, etc. Whorls more swelled than _E. su._, two-banded.

PLATE XVI.

CHEMNITZIA.

Fig.

1. C. ELEGANTISSIMA, _Mont._ (_Turbo._)--_T. lacteus_, Linn.?, _T. acutus._--Brit. co. generally; not deep, C. Interstices of longitudinal ribs smooth.

2. C. SIMILLIMUS, _Mont._ (_Turbo._)--_C. gracilis_, Phil. More slender and minute than f. 1.

3. C. PUSILLA, _Phil. Moll. Sic._ 2. _p._ 224. _pl._ 28. _f._ 21.--More stout than f. 1, with the ribs straight and broad. Medit., Brit.?

4, 5. C. RUFA, _Phil._--And var. _C. fulvocincta_ (f. 5).--Brit. co. generally, 15 to 50 fath., Mc. Spiral grooves between ribs.

6. C. FORMOSA, _Jeffreys_, (_Odostomia._)--Swansea, Shellness, Bantry Bay, etc., Mr. Grooved between ribs, excavated at suture.

7. C. FENESTRATA, _Forbes and Jeffr._ (_Odostomia._)--Torbay, etc., R. With pits between spiral ridges.

8. C. RUFESCENS, _Forbes._--_Odostomia_ and _Turritella indistincta_ and _scalaris_.--Clyde, Hebrides, Oban, 15 to 50 fath., R. More stout than _C. rufa_. Three-banded.

9. C. SCALARIS, _Philippi_, (_Melania._)--Exmouth, Guernsey, Medit., R. Ribbed; whorls angular above.

10. C. CLATHRATA, _Jeffreys._--Birterbuy Bay, R. Lower part of whorls spirally grooved between ribs.

11. C. INDISTINCTA, _Mont._ (_Turbo._)--_Odost._, _Turritella_, _Terebra_, and _Pyramis truncata_ and _speciosa_, etc.--Brit. co. generally, 5 to 40 fath., Mr.; S. Eu. Ribs curved, striated between.

TRUNCATELLA.

12. T. SUBCYLINDRICA, _Linn._ (_Helix._)--_T. Montagui_, _Turbo truncatus_, _subtruncatus_, _Cyclostoma truncatulum_, _Turritella t._ and _s._, etc.--Weymouth, S. Devon, Scarborough, etc., C.

NATICA.

13. N. HELICOIDES, _Johnston._--Scotland, Scarborough, etc., 15 to 40 fath., R.; N. Eu. Thin-grooved suture.

14. N. MONTAGUI, _Forbes._--_Nerita rufa_, _Natica r._ and _rutilla_.--Principally northern loc. In sand and gravel, 12 to 90 fath., Mr. Small, stout.

15. N. KINGII, _Forbes and Hanley._--Northumberland, unique, _Jeffreys_ coll.

16. N. NITIDA, _Donovan._--_Nerita_ and _Natica catena_, _nitida_, _Alderi_, _glaucina_, etc.--Brit. co. generally, 4 to 90 fath., C. Oblique, marked with undulating lines.

17. N. MONILIFERA, _Lamk._--_Nerita glaucina_, _catena_, etc.--Near water-mark, in sandy places generally, C. Whorls rounded.

18. N. SORDIDA, _Phil._--_N. fulva_, _plumbea_, etc.--Scilly, Cape Clear, Zetland, etc., 25 to 90 fath., R.

19. N. PUSILLA, _Say._--_N. Groenlandica_, _livida_, _alba_.--Northumberland, Yorkshire, N. Eu., 45 fath., R. White; umbilicus small.

RECLUZIA.

20. R. APERTA, _Jeffreys._--_Natica aperta_, Lovén?--Zetland, Rr.

VELUTINA.

21. N. LÆVIGATA, _Linn._ (_Helix._)--_Bulla_, _Velutina_, etc.--Brit. co. generally, 1 to 30 fath., N. Eu., C.

22. N. FLEXILIS, _Mont._ (_Bulla._)--_Coriocella_ and _Sigaretus plicatilis_.--N. Scot., 25 fath., Rr.

LAMELLARIA.

23. L. PERSPICUA, _Linn._--_Helix_, _Bulla haliotoidea_, _Sigareta_ and _Coriocella neritoideus_.--Brit. co. generally, but R.; 1 to 15 fath., Mr. Thin, glassy, more ventricose than _L. tentaculata_.

24. L. TENTACULATA, _Mont._--_Sig._ and _Cor._--Falmouth, Swansea, Arran, etc. Laminarian, Mr. Upper whorls less full than _L. perspicua_.

OTINA.

25. O. OTIS, _Turt._ (_Helix._)--_Velutina_, _Galericulum ovatum_.--Wales, Devon, Channel Isls., Clare, etc., Mc. Littoral.

TRICHOTROPIS.

26. T. BOREALIS, _Broderip and Sowb._--_T._ and _Murex carinatus_, _umbilicatus_, _acuminatus_, etc.--N. Scotland, W. Ireland, 15 to 80 fath., R.

PLATE XVII.

ODOSTOMIA.

Fig.

1. O. UNIDENTATA, _Mont._ (_Turbo._)--_Voluta u._, _O. plicata_.--Brit. co. generally, Mc. Rather conical. Tooth strong; no epidermis.

2. O. TURRITA, _Hanley_, _Brit. Mar. Conch._--_O. unidentata_, var. B. M.--R. More lengthened than No. 1.

3, 4. O. ACUTA, _Jeffreys._--Torbay, Loch Fyne, Galway, etc., Mc. Strong, conical. Suture deep.

5. O. PLICATA, _Mont._ (_Turbo._)--_Voluta p._, _V. plicatula_, _O. Annæ_, _Jaminia p._, etc., Mc.--Salcombe, Swansea, Dublin, Aberdeen, Mc. Turreted. Narrow, thin.

6. O. INSCULPTA, _Mont._ (_Turbo._)--_Voluta_, _Jaminia_, and _O. ins._--S. Devon, Oban, Hebrides, etc., R. Conical, spirally striated.

7. O. PALLIDA, _Mont._ (_Turbo._)--_Vol._, _Cingula_, _Phasianella p._, _O. ambigua_.--S. Devon, Rr. Broad. Thin, pillar straight.

8. O. CONOIDEA, _Brock._--_Turbo_, _Odost._, etc.--N. Scotland, Mc. S. Devon, Mr. N. and S. Eu. White. Whorls straight; throat striated.

9. O. CONSPICUA, _Alder._--Isl. Man, Whitburn, Herm. Coloured. Whorls rounded; throat striated.

10. O. TRUNCATULA, _Jeffreys._--Plymouth. Elongated.

11. O. CYLINDRICA, _Alder._--_Turbo nivosus_?--S. Devon, Ilfracombe, Guernsey, Cork, R. Cylindrical, few whorls.

12, 13. O. EULIMOIDES, _Hanley._--_O. crassa_, _O. pallida_ (var. f. 13), _O. notata._--Brit. co. generally. Coralline zone, Mr. Ample body-whorl.

14. O. DUBIA, _Jeffr._--S. Devon, Lerwick, Guernsey, Mr. Rather large body-whorl.

15, 16. O. ALBA, _Jeffreys_, (and var.)--Swansea, Skye, Zetland, Guernsey, Mr. Thin, whorls rounded.

17. O. NITIDA, _Alder._--S. Devon. Littoral, Mc. Aperture differently formed from No. 17.

18. O. LUKISII, _Jeffreys_, _Ann. Nat. Hist. 1859._--Guernsey. Sublittoral and coralline, Mc. Whorls tumid; a slight umbilicus.

19. O. GLABRATA, _Muhlfeldt_, (_Helix._)--_Rissoa punctulum_, etc.--Zetland, R. Pillar-lip thin, arched.

20. O. RISSOIDES, _Hanley._--_O. scalaris._--Channel Isls., Devon, Cornwall, Tenby, etc., Mc. Thin, conical, no umbilicus.

21. O. ALBELLA, _Lovén._--_O. rissoides_, var., B. M.--Guernsey, S. Devon, etc. Turreted, upper whorls more cylindrical than No. 20.

22. O. OBLIQUA, _Alder._--Tynemouth, Guernsey, 7 fath. to deep water, Rr. Thin, oblique.

23. O. DIAPHANA, _Jeffr._ _Ann. Nat. Hist. New Ser. vol._ ii. _p._ 341.--R. Manifestly distinct from No. 22.

24. O. STRIALATA, _Alder._--Northumberland, Rr. Conical, striated.

25. O. MINIMA, _Jeffreys_, _Ann. Nat. Hist. Jan. 1, 1858._

26. O. INTERSTINCTA, _Mont._ (_Turbo._)--_T._, _O._, _Voluta_, and _Jaminia canaliculata_, _oblonga_, and _obtusa_.--Brit. co. generally. Shallow water, C. With longitudinal ribs.

27. O. DOLIOLIFORMIS, _Jeffr._--Scarborough, Exmouth, Swansea, Tenby, Rr., Scotland. Oval, body-whorl very tumid.

28. O. WARRENII, _Thompson_, (_Rissoa_.)--_Turbonilla_ and _O. obliqua_, _O. decorata_.--Dublin, S. Devon, W. Scotland, R. Turreted. Mouth oblique; an umbilicus; no fold or columella.

29. O. SPIRIALIS, _Mont._ (_Turbo._)--_Voluta_ and _Rissoa s._, _pellucida_, and _plicatula_.--Brit. co. generally, not deep, Mc. Whorls ribbed longitudinally above, spirally beneath.

30. O. DECUSSATA, _Mont._ (_Turbo._)--_T. Helix_, _Rissoa_ and _O. arenaria_, _pellucida_?, and _d._--Exmouth, Lerwick, etc., R. Ribbed and spirally striated.

31. O. EXCAVATA, _Phil._ (_Rissoa_.)--_R._, _O._, and _Cingula Harveyi_ and _Deshayesiana_.--Dublin, Arran, Guernsey, R. Largely sculptured.

PLATE XVIII.

TRITON.

Fig.

1. T. CUTACEUS, _Linn._--Channel Isls., Rr. as Brit. Mr. Lukis's specimen taken living off Guernsey.

2. T. NODIFERUS, _Lamk._--Guernsey; three living specimens, one incrusted with _Lepralia coccinea_ (truly British). Mr. Jeffrey's specimen reduced.

MUREX.

3. M. ERINACEUS, _Linn._--_Purpura scalata_, var. _M. Tarentinus_.--Brit. co. generally; 5 to 30 fath., C. N. and S. Eu.

4. M. CORALLINUS, _Scacchi._--_Fusus_ and _M. lavatus_, _inconspicuus_, _gyrinus_, and _badius_?--Channel Isls. and S. Eu., C.