Chapter V: Introduction (3)

_Animal._ Body much compressed; mantle cleft throughout its circumference, except along the back, and garnished at its free edge with a double row of very short tentacular cirri; foot small, canaliculated; a byssus; mouth surrounded with fringed lips, besides two pair of labial appendages, a large contractile muscle, nearly posterior.

_Shell._ Foliaceous or not; always nacred, subequivalve, of a subregular form, but somewhat variable; valves oblique, the left one with a little notch, through which the byssus passes; hinge linear, toothless, or with two small rudimentary teeth; ligament more or less exterior, placed in a narrow groove; one very large posterior muscular impression and one very small anterior. Inhabits the British and American coasts. Nineteen species.

Avicula nudata. A. macroptera. A. semi-sagitta. A. falcata. A. Tarentina. A. squamulosa. A. Costellata. A. lotaria. A. heteroptera. A. crocea. A. Atlantica. A. papilionacea. A. physoides. A. virens. A. trigonata. A. phalænacea.

· · · · ·

A. hirundo.* A. pallida.* A. nebulosa.*

5. Genus _Meleagrina_. Pl. IX.

_Animal._ As above.

_Shell._ Subequivalve, rounded, squamous, a sinus posteriorly for the passage of the byssus, at which place the left valve is notched and narrow; hinge linear and destitute of teeth; ligament marginal, elongated, partly exterior, and dilated in the centre. Inhabits the Indian Ocean. Two species, of which the first is the pearl-oyster.

Meleagrina margaritifera. M. albina.

FAMILY XVIII.

PECTINEA. Seven genera.

1. Genus _Pedum_. Pl. IX.

_Animal._ Unknown, but probably byssiferous.

_Shell._ Subtriangular, inequilateral, inequivalve, with rounded summits, freely marked, unequal and distant: the right valve inflated, widened at its inferior and posterior edge, sloped anteriorly, and subauriculated, the left not being so; hinge toothless, anterior or buccal; ligament inserted in an oblique cavity prolonged outwardly to the summits, and carried within into a spoon-like cavity. Inhabits the Indian Ocean. One species.

Pedum spondyloideum.

2. Genus _Lima_. Pl. IX.

_Animal._ Body moderately compressed; a byssiferous abdominal appendage; edges of the mantle furnished with tentacular cirri in several rows; mouth surrounded with a very thick fringed lip.

_Shell._ Oval, more or less oblique, nearly equivalve, subauriculated, regularly gaping at the anterior portion of the inferior edge; summits anterior and distant; hinge buccal, longitudinal, toothless; ligament rounded, nearly exterior, inserted in an excavation in each valve; a central muscular impression, divided into three very distinct parts. Inhabits the Indian, Australasian, American, and Mediterranean seas. Six living species. Eleven fossil.

Lima inflata. L. squamosa. L. annulata. L. glacialis. L. fragilis. L. linguatula.

3. Genus _Pecten_. Pl. IX.

_Animal._ Body more or less compressed, orbicular; mantle furnished with a single row of tentacular papillæ, and with small oculiform, pedunculated disks, with regular spaces between them; rudiment of a canaliculated foot, and a byssus; mouth surrounded with fleshy appendages, irregularly ramified.

_Shell._ Free, regular, thin, solid, equivalve, equilateral, auriculated; summits contiguous; hinge toothless, a ligamentous membrane throughout all its extent, besides a short, thick, ligament, almost altogether internal, and filling a triangular excavation under the summit; a single subcentral muscular impression. Found in almost all seas. Sixty-two species; and, according to Defrance, ninety-eight fossil.

Pecten maximus. P. Jacobæus. P. bifrons. P. zigzag. P. medius. P. Latirentii. P. pleuronectes. P. purpuratus. P. pallius. P. impricatus. P. asperimus. P. varius. P. glaber. P. grisens. P. flabellatus. P. quadradiatus. P. Tranquebaricus. P. hybridus. P. obliteratus. P. Magellanicus. P. lineolaris. P. nodosus. P. pusio. P. gibbus. P. ornatus. P. florens. P. opercularis. P. tigris. P. histrionicus. P. turgidus. P. aspersus. P. plicus. P. rastellus. P. flagellatus. P. flavidulus. P. Japanicus. P. radulus. P. pes-felis. P. sauciatus. P. aurantius. P. sinuosus. P. virgo. P. Isabella. P. flexuosa. P. inflexus. P. miniaceous. P. lividus. P. sulcatus. P. unicolor. P. distans. P. irradians. P. dispar. P. Islandicus. P. sulphureus. P. pellucidus. P. sanguineous. P. senatorius. P. lunatus. P. lineatus.

· · · · ·

P. dislocatus.* P. concentricus.* P. monotimeris.* P. Latiauratus* P. Pealii.*

4. Genus _Plagiostoma_. Pl. IX.

_Animal._ Entirely unknown.

_Shell._ Moderately thick, regular, free, subequivalve, subauriculated, the two valves nearly equally dilated, both provided with a distinct summit reflexed to the middle of a plane surface, with a large triangular slope in the middle; articulation transverse, straight, and by two distant lateral condylæ. Ten species. Fossils only.

5. Genus _Plicatula_. Pl. IX.

_Animal._ Unknown.

_Shell._ Solid, adhering, subirregular, inauriculated, inequivalve, pointed at the summit, rounded and subplicated posteriorly; inferior valve without heel; hinge cephalic, longitudinal, provided upon each valve with two strong teeth, entering in corresponding cavities; ligament altogether internal and inserted in a median cavity. Inhabits the American seas. Five species.

Plicatula ramosa. P. depressa. P. cristata. P. Australis. P. reniformis.

6. Genus _Spondylus_. Pl. IX.

_Animal._ Body moderately compressed, provided inferiorly with a rudiment of a foot, without byssus; mantle open in all its inferior and superior portion; mouth surrounded with very thick and fringed lips.

_Shell._ Solid, adhering, subregular, more or less spined, subauriculated, inequivalve; the right or inferior valve fixed, much more excavated than the other, and having posteriorly at the summit a triangular face enlarging, and elongating with age; hinge longitudinal, provided in each valve with two strong teeth entering corresponding cavities; ligament short, nearly median, partly exterior; muscular impression single and subdorsal. Found in all the seas of hot climates, and even in the Mediterranean. Four or five fossils are found in France, one in South America. Twenty-one species.

Spondylus candidus. S. coccineus. S. spathuliferus. S. gædaropus. S. arachnoides. S. multilamellatus. S. longitudinalis. S. costatus. S. longispinous. S. regius. S. variegatus. S. avicularis. S. zonalis. S. crassisquama. S. ducalis. S. violascens. S. microlepos. S. crocens. S. radians. S. aurantius.

· · · · ·

S. Americanus.*

7. Genus _Podopsis_. Pl. IX.

_Animal._ Unknown.

_Shell._ Subregular, somewhat thick, equilateral, symmetrical, inequivalve, adhering by the extremity of the shorter valve; the other terminating in a pointed, reflexed, and median summit. Two fossil species.

FAMILY XIX.

OSTRACEA. Six genera.

1. Genus _Ostrea_. Pl. IX.

_Animal._ Body compressed, more or less orbicular; edges of the mantle thick, not adhering or retractile, and provided with a double row of short and numerous tentacular filaments; two pairs of elongated and triangular labial appendages; a subcentral bipartite muscle.

_Shell._ Irregular, inequivalve, inequilateral, roughly foliaceous, the left or inferior valve adhering, larger and deeper than the other, its summit prolonged with age into a sort of heel; the right or superior valve more or less operculiform; hinge oral, toothless; ligament subinterior, short, inserted in an oblong cardinal cavity increasing with the summit; muscular impression single and subcentral. Found in all seas near the mouths of rivers. Defrance enumerates one hundred and twenty species. Lamarck thirty-three fossil, forty-nine living.

Ostrea edulis. O. ruscuriana. O. borealis. O. cochlear. O. gallina. O. lingua. O. Braziliana. O. rostralis. O. denticulata. O. cornucopiæ. O. doridella. O. Limacella. O. hippopus. O. Adriatica. O. cristata. O. numisma. O. tulipa. O. scabra. O. parasitica. O. spathulata. O. cucullata. O. rubella. O. erucella. O. labrella. O. radiata. O. Canadensis. O. mytiloides. O. trapezina. O. rufa. O. gibbosa. O. eliptica. O. deformis. O. plicatula. O. fusca. O. cristagalli. O. virginica. O. excavata. O. simuata. O. tuberculata. O. Magaritacea. O. Australis. O. haliotidæa. O. fucorum. O. glaucina. O. turbinata. O. folia. O. hyotis. O. imbricata.

· · · · ·

O. semicylindrica.*

2. Genus _Gryphæa_. Pl. IX.

_Animal._ Unknown.

_Shell._ More finely lamellated than in the _Ostrea_, free, or slightly adhering, subequilateral, very inequivalve; the inferior valve very concave, with a summit more or less recurved in a hook; the superior opiculiform and much smaller; hinge toothless; ligament inserted in an elongated and arcuated cavity; a single muscular impression. Habitation unknown. One species.

Gryphæa augulata.

3. Genus _Vulsella_. Pl. IX.

_Animal._ Body elongated and compressed; mantle much prolonged posteriorly, and edged with two rows of very close tubercular papillæ; a moderately large abdominal foot, proboscidiform, canaliculated, without byssus; a very large transversal mouth with well-developed triangular labial appendages; branchiæ narrow, very long, and united in nearly all their extent.

_Shell._ Subnacred, irregular, flat, elongated, subequivalve, inequilateral, with summits anterior, distant and flexed inferiorly; hinge oral and toothless; ligament undivided, thick, inserted in a round pit excavated in a projecting apophysis upon each valve; a moderately large subcentral muscular impression, and two very small ones altogether anterior. Inhabits the Indian and Australasian seas. Six living species. One fossil.

Vulsella hians. V. rugosa. V. spongiarum. V. lingulata. V. mytilina. V. ævata.

4. Genus _Placuna_. Pl. IX.

_Animal._ Entirely unknown.

_Shell._ Free, subirregular, very fine, almost entirely translucid, flat, subequivalve, subequilateral, slightly auriculated; hinge altogether internal, formed upon the superior valve, which is the smaller, by two elongated, unequal, oblique, crests; converging to the summit, at the internal side of which a ligament is attached in the form of a V, a single, small, subcentral muscular impression. Inhabits the Indian seas. Two fossils in France. Three living species.

Placuna sella. P. papyracea. P. placenta.

5. Genus _Anomia_. Pl. IX.

_Animal._ Much compressed; edges of the mantle very fine; not adhering, and furnished exteriorly with a row of tentacular filaments; contractile muscle thick, divided into three parts, the largest of which passes partially across a slope of the inferior valve, and often contains a calcareous substance or small bone, adhering to marine bodies.

_Shell._ Adhering, irregular, inequivalve, inequilateral, ostraceous; inferior valve a little flatter than the superior, divided at the summit into two sloping branches, whose approximation forms a large oval hole; the superior valve, which is the larger, has an oval excavation under the summit; a subcentral muscular impression, divided into three parts. Inhabits the British coasts. Two beautiful species are found on the shores of Rhode Island and New Jersey. Nine species.

Anomia patellaris. A. pyriformis. A. lens. A. cepa. A. electrica. A. membranacea. A. squamula.

· · · · ·

A. ephippium.* A. fornicata.*

6. Genus _Crania_. Pl. IX.

_Animal._ See Anomia.

_Shell._ Orbicular, the upper valve gibbous and conical; lower valve, flat, with three perforations. Inhabits the Indian Ocean. One species.

Crania orbicula.

FAMILY XX.

BRACHIOPODA. Three genera.

1. Genus _Orbicula_. Pl. IX.

_Animal._ Body much compressed and rounded; mantle open throughout its whole circumference; two ciliated tentacular appendages.

_Shell._ Orbicular, much compressed, inequilateral, very inequivalve; inferior valve very thin, adhering, imperforated, the superior patelloid, with the summit more or less inclined towards the posterior side. Inhabits the Norwegian seas. One living species. Two fossil.

Orbicula Norwegica.

2. Genus _Terebratula_. Pl. IX.

_Animal._ Depressed, circular or oval, more or less elongated, with two, long, pectinated, labial tentacula.

_Shell._ Thin, inequivalve, regular, subtrigonal; one of the valves larger and more dilated than the other, which is sometimes operculiform; hinge condyloid, in a straight line, and formed by two oblique articular surfaces in one valve placed between corresponding projections in the other. Inhabits the sea at the Zetland Islands. Two species are found in America. Thirteen living species. Thirty-eight fossil.

Terebratula dilatata. T. flavescens. T. dorsata. T. Vitrea. T. dentata. T. globosa. T. caput-serpentis. T. psittacea. T. rotunda. T. pisa. T. sanguinea.

· · · · ·

T. septentrionalis.* T. truncata.*

3. Genus _Lingula_. Pl. IX.

_Animal._ Depressed, oval, somewhat elongated, inclosed between two lobes of a mantle, slit throughout its anterior half, and having pectinated branchiæ adhering to the internal surface; mouth simple, having on each side a long tentacular appendage ciliated in all its external edge, and rolling itself up spirally in the shell.

_Shell._ With an epidermis, subequivalve, equilateral, depressed, elongated, truncated anteriorly; the summit median and posterior; no trace of ligament; a long fibro-gelatinous peduncle fixing the shell vertically to submarine bodies; muscular impression multiple. Inhabits the Indian Ocean. One species.

Lingula anatina.

CLASS IV.
MOLLUSCA.

Animals soft, inarticulated, furnished with an anterior head, projecting or salient; most frequently with eyes and tentaculæ, or possessing, at their summit, arms disposed in the form of a coronet: their mouth either short, elongated, or tubular, exsertile, and generally armed with hard parts. Mantle diversified, having its edges free on the sides of the body, or the lobes united, forming a sack, which in part envelopes the animal; gills or respiratory organs various, circulation double, one particular, the other general; heart unilocular, sometimes with the auricles divided, and very distant; no medullary cord along the body, but scattered nerves and ganglions. Twenty-two families.

FAMILY I.

PTEROPODA. Six genera.

Some genera of this family are without a testaceous covering, mentioned only to preserve the family entire.

1. Genus _Hyalæa_. Pl. IX.

_Animal._ Body enclosed in a shell, winged before, two opposite wings, somewhat retractile, inserted at the sides of the mouth, head distinct, mouth terminal, placed at the junction of the fins; without eyes.

_Shell._ Symmetrical, very thin and transparent, valves unequal, flat above, convex below, open like a cleft anteriorly, summit truncated and tridentated posteriorly. Inhabits the Mediterranean. Two species.

Hyalæa tridentata. H. cuspidata.

2. Genus _Clio_. Pl. IX.

_Animal._ Body free, naked, more or less elongated, tapering to the rear, head very distinct; provided with six, long, conical, retractile tentaculæ, separated into two groups of three each; mouth altogether terminal and vertical, eyes sessile, rudiment of a foot under the neck.

This is a molluscous animal without any testaceous covering, but is here placed as leading to other genera which have shells. Inhabits the Indian seas. Two species.

Clio borealis. C. Australis.

3. Genus _Cleodora_. Pl. IX.

_Animal._ Body oblong, gelatinous, contractile; a head in front with two wings, and the posterior part enveloped in a shell, head distinct, projecting and round; two eyes; mouth in the form of a small beak; destitute of tentaculæ; two, opposite, membranaceous, pellucid, and cordated wings, placed at the base of the neck.

_Shell._ Pyramidal, triangular, of a gelatinous or cartilaginous substance, very thin and transparent; aperture obliquely truncated. Inhabits the South American seas. Two species.

Cleodora pyramidata. C. caudata.

4. Genus _Limacina_. Pl. IX.

_Animal._ Body soft, oblong, two branchial fins situated at the base of the neck; posterior part of the body spiral, and enveloped in a shell.

_Shell._ Thin, fragile, papyraceous, spiral, the whorls reunited in a planorbis form, and deeply and largely umbilicated on one side; aperture large and entire. Inhabits the North seas. One species.

Limacina helicialis.

5. Genus _Cymbulia_. Pl. IX.

_Animal._ Body oblong, gelatinous, pellucid, enclosing a shell; head sessile; two eyes, and two retractile tentacula; mouth with a retractile proboscis; two, opposite, oblong, ovate, branched wings, connate at their posterior base.

_Shell._ Gelatinous, cartilaginous, very transparent, crystalline, oblong, in shape of a shoe, from which it has derived the name of the slipper, truncated at the summit; aperture lateral and anterior. Inhabits the Mediterranean. One species.

Cymbulia Peronii.

6. Genus _Pneumodermon_. Pl. IX.

A molluscous animal, without any testaceous covering, and much resembling the genus Clio. Inhabits the Indian seas. One species.

Pneumodermon Peronii.

FAMILY II.

PHYLLIDIACEA. Six genera.

1. Genus _Phyllidia_. Pl. IX.

A mollusca similar to the preceding genus, without a shell, but its back covered with a rough or coriaceous skin. Inhabits the Mediterranean. Three species.

Phyllidia varicosa. P. pustulosa. P. ocellata.

2. Genus _Chitonellus_. Pl. IX.

_Animal._ Body creeping, elongated; middle of the back provided its entire length with a detached, multivalve shell; the alternate pieces for the most part longitudinal; sides naked; branchiæ disposed around the body; foot cleft longitudinally by a deep furrow.

_Shell._ Each valve with striæ radiating from its apex; the margins serrated; the base of the last valve obtuse. The testaceous plates of this genus are never joined like those of the Chiton, so that the animal can move in every direction. Upon the contraction of the animal after death, however, these valves become nearly united. Inhabits the seas of New Holland. Two species.

Chitonellus striatus. C. larvæformis.

3. Genus _Chiton_. Pl. IX.

_Animal._ Body creeping, ovate oblong, convex, round at both extremities; marginated with a coriaceous skin: the back covered by a longitudinal series of testaceous, transverse, imbricated, and moveable plates; head before, sessile, with the mouth placed below, destitute of tentacula or eyes; branchiæ placed round the body, under the margin of the skin; and orifice at the posterior extremity.

_Shell._ Eight imbricated valves, nearly smooth, slightly carinated, and rounded at the margins: summit more or less marked and curved by longitudinal elongations. Inhabits the British and American coasts. Sixty-three species.

Chiton fulvus. C. pisceus. C. ruber. C. lævis. C. spinosus. C. fascicularis. C. marginatus. C. crinitus. C. siculus. C. niger. C. spiniferous. C. coquimbensis. C. lumingii. C. granosus. C. glauco-sinctus. C. disjunctus. C. elegans. C. lineatus. C. sulcatus. C. bicolor. C. cerasimus. C. Magellanicus. C. marmoratus. C. nebulosus. C. olivaceous. C. latus. C. punctatus. C. viridus. C. cinerus. C. tunicatus. C. gigas. C. squamosus. C. Peruvianus. C. tesselatus. C. capensis. C. Carmichaelis. C. echinatus. C. striatus. C. lineolatus. C. chilensis. C. tuberculatus. C. hispidus. C. thalassimus. C. porosus. C. larvaformis. C. undulatus. C. luteolus. C. fuscus. C. minimus. C. cimex. C. ascellus. C. Icelandicus. C. fasciatus. C. setosus. C. variegatus. C. asselloides. C. indus. C. albas. C. castaneus.

· · · · ·

C. Emersonii.* C. fulminatus.* C. amœna.* C. alternata.* C. sagrinatus.*

4. Genus _Patella_. Pl. IX.

_Animal._ Body completely covered by the shell; head with two acute tentaculæ, and the eyes situated at their exterior base; branchiæ placed under the mantle and around the body.

_Shell._ This numerous and beautiful genus of Linnæus has been subdivided into the several distinct genera of Fissurella, Emarginula, Navicella, Umbrella, Pileopsis, Calyptrea, Crepidula, Parmophora, and Ancylus; each of which possesses sufficiently well-defined characters to authorize a separation, by which they may be more easily distinguished from the still widely extended family of Patella. Oval, conic, or a little depressed, outside green or brown, sometimes radiated with various colours; having divergent striæ and concentric wrinkles, inside glossy, iridescent, with yellow or fawn-coloured, purple, blue, or brown radiations. Inhabits almost every coast. Forty-nine species.

Patella safiana. P. testitudinaria. P. cochlear. P. compressa. P. granularis. P. decaurata. P. Magellanica. P. stellifera. P. vulgata. P. mammillaris. P. lineata. P. leucopleura. P. notata. P. Tarentina. P. punctata. P. puncturata. P. Javanica. P. tuberculifera. P. miniata. P. pellucida. P. tricostata. P. Australis. P. apicina. P. granatina. P. oculus. P. Galathia. P. pectinata. P. viridula. P. scutellar. P. radians. P. cærulea. P. plumbia. P. umbrella. P. pyramidata. P. luteola. P. aspera. P. spinifera. P. longicosta. P. barbata. P. angulosa. P. saccharina. P. laciniosa. P. plicata.

· · · · · P. amœna.* P. alternata.* P. alveus.* P. candida.*

5. Genus _Umbrella_. Pl. IX.

_Animal._ Body very thick and oval, provided with a dorsal shell; foot large, smooth, and flat, surrounded by a border, anteriorly notched, attenuated behind; head indistinct; four tentacula, the two upper ones thick, short, and truncated, the other two thin, and shaped like pedunculated crests; having foliaceous branchiæ.

_Shell._ External, orbicular, subirregular, nearly flat, slightly convex above, white, with apex near the middle; margin acute, internal surface rather concave; having a callous disk, coloured, depressed in the centre, surrounded by a smooth border. Inhabits the Indian Ocean. Two species.

Umbrella Indica. U. Mediterranea.

6. Genus _Pleurobranchus_. Pl. IX.

_Animal._ Body creeping, fleshy; mantle and foot expanded; branchiæ placed on the right side; cloak enveloping the shell; neck short, contracted in some species, with an emarginate front, exhibiting the commencement of the inferior tentacula, the upper ones tubular and cloven; gills at the edge of the dorsal plait, mouth provided with a short, retractile proboscis.

_Shell._ Depressed, oval, oblong, concentrically wrinkled, almost entirely open, rounded and convoluted; the vertex with a single turn. Inhabits the coast of Devonshire in England. Two species.

Pleurobranchus Peronii. P. Laqueare.

FAMILY III.

CALYPTRACEA. Seven genera.

1. Genus _Parmophorus_. Pl. IX.

_Animal._ Body creeping, thick, oblong-ovate, broad behind, obtuse at the extremities; border of the mantle cleft before, and suspended vertically around; head distinct, and slit below; two conical contracted tentacula, at the base of which are placed the eyes, which are somewhat pedunculated; mouth below, funnel-shaped, oblique, truncated, and concealed; branchial cavity opening anteriorly behind the head by a transverse fissure.

_Shell._ Oblong, very depressed, slightly convex above, obtuse at extremities, anteriorly channeled by a slight sinus, and having towards the posterior part a small pointed apex, inclined backwards; the lower surface slightly concave. Inhabits the Australian seas. Four species. One fossil.

Parmophorus Australis. P. brevicula. P. granulata. P. ambigua.

2. Genus _Emarginula_. Pl. IX.

_Animal._ Body creeping, with two, conical, tentacular eyes at the external base; mantle large, partly covering the margin of the shell; foot very large and thick.

_Shell._ Shield-like, conical; summit inclined; the cavity simple, having a notch or hollow cut on its posterior margin; shells of this genus are generally very small. Inhabits the British seas. Five species.

Emarginula Blainvillii. E. Cuvierii. E. fissura. E. rubra. E. marginata.

3. Genus _Fissurella_. Pl. IX.

_Animal._ With the head truncated in front; two conical tentacula, with eyes at their exterior base; mouth simple, terminal, and destitute of jaws; two pectinated branchiæ projecting from the cavity; mantle large, protruding beyond the shell.

_Shell._ Shield-shaped, conical recurved, summit entire, depressed, concave below, perforated at the summit in the form of a key hole, without a spire; the exterior surface ribbed longitudinally. Inhabits the European and American seas. Twenty-two species.

Fissurella Cayennensis. F. lilacina. F. Javanicensis. F. fascicularis. F. rosea. F. Barbadensis. F. radiata. F. nodosa. F. nimbosa. F. crassa. F. Græca. F. picta. F. pustula. F. hiantula. F. viridula. F. depressa. F. Peruviana. F. gibberula. F. minuta. F. plicata.

· · · · ·

F. alternata.* F. redimicula.*

4. Genus _Pileopsis_. Pl. X.

_Animal._ With two conical tentacula, and the eyes at their base; branchiæ formed in a row under the anterior margin of the cavity, near the neck.

_Shell._ Obliquely conical, anteriorly recurved, apex bent, almost spiral; aperture rounded, elliptical, the anterior margin shortest, acute, slightly sinuated; the posterior largest and rounded. One elongated and arched muscular impression, situated under the posterior margin. Inhabits the seas of Europe. Nine species.

Pileopsis intorta. P. subrufa. P. spirirostris. P. retortella. P. ungarica. P. mitula. P. pennata. P. squamæformis. P. depressa.

5. Genus _Calyptrea_. Pl. X.

_Animal._ The same as preceding genus.

_Shell._ This genus derives its common name, “the Cup-and-Saucer Limpit,” by having in the interior cavity a cup-shaped appendage, which is sometimes vertical, and sometimes like a horse-shoe, with a muscular impression of variable form, vertex ending in a small volution; smooth, margin entire, very glossy within, and provided with a laminar plate. Inhabits the Chinese and S. American seas. Nine species.

Calyptrea porcellana. C. equestris. C. fornicata. C. peziza. C. angulata. C. tecum-sinense. C. scutellata. C. poculum.

· · · · ·

C. striata.*

6. Genus _Crepidula_. Pl. X.

_Animal._ Head anteriorly forked, having two conical tentacula, with the eyes placed at their exterior base; mouth simple, destitute of jaws, and situated in the bifurcation of the head; branchiæ with tufts and projecting from the branchial cavity; the mantle never bordering the shell; foot minute, orifice lateral.

_Shell._ Ovate, or oblong; the back almost always convex, concave beneath; the spire very much inclined towards the margin; the aperture partly closed by a horizontal lamina. Inhabits the American seas. Thirteen species.

Crepidula extinctorum. C. aculeata. C. lævigata. C. uguiformis. C. dilata. C. Peruviana. C. gigas.

· · · · ·

C. fornicata.* C. depressa.* C. glauca.* C. plana.* C. intorta.* C. convexa.*

7. Genus _Ancylus_. Pl. X.

_Animal._ Body creeping, enveloped in the shell; two compressed subtruncated tentacular, with eyes situated at their internal base; foot short, elliptical; somewhat narrower than the body.

_Shell._ Thin, obliquely conical; aperture oval, with a pointed apex, which very much inclines backwards; margins simple. This is a fresh water shell, found in the lakes of Europe and rivers of America. Five species.

Ancylus lacustris. A. fluviatilis. A. spinarosæ.

· · · · ·

A. rivularis. A. filosus.

FAMILY IV.

BULLACEA. Three genera.

1. Genus _Acera_.

_Animal._ Body ovate, convex, transversely divided above into two parts; the foot with dilations in the form of wings below; head indistinct; branchiæ situated on the back, greatly behind, and covered by a mantle destitute of a shell. Inhabits the Mediterranean. One species.

Acera carnosa.

2. Genus _Bullæa_. Pl. X.

_Animal._ Body ovate, somewhat convex above, and divided into two parts transversely; lateral lobes of the foot very thick; head indistinct, and without tentacula; branchiæ placed on the back.

_Shell._ Concealed in the mantle, very thin, rolled and spiral on one side; without a columella and spire; aperture very large and wide, dilated at the upper part. Inhabits the British seas. Two species.

Bullæa aperta. B. striata.

3. Genus _Bulla_. Pl. X.

_Animal._ Body oblong-ovate, slight convexity; divided into two portions transverse above, mantle slightly folded posteriorly; visible tentacula; branchiæ dorsal and covered, opening only on the right side.

_Shell._ Univalve, ovate globular, convolute, no columella, spire not projecting but visible, aperture the whole length of the shell, external margin sharp and smooth. Inhabits the British and American seas. Nineteen species.

Bulla physis. B. naucum. B. hydatis. B. rugosa. B. fragilis. B. aplustre. B. ampulla. B. lignaria. B. fasciata. B. striata. B. Wyatii. B. solida. B. cornea. B. lactea.

· · · · ·

B. solitaria.* B. triticea.* B. hiemalis.* B. Gouldii.* B. lineolata.*

FAMILY V.

APLYSIACEA. Two genera.

1. Genus _Dolabella_. Pl. X.

_Animal._ Body creeping, oblong, narrowed in front; and posteriorly widened; area round, sloping, and truncated obliquely; margins folded over the back; four tubular tentacula, disposed in pairs; bronchial operculum inclosing a shell; orifice dorsal, near the branchiæ.

_Shell._ Oblong, slightly arcuated, thick, callous, and somewhat spiral on both sides, singular in formation, and its characteristic unlike most other shells. Inhabits the Isle of France. Two species.

Dolabella Rumphii. D. fragilis.

2. Genus _Aplysia_. Pl. X.

_Animal._ Body creeping, oblong, convex above; bordered on each side by a broad mantle, which covers the back when the animal is in repose; head and neck elevated, with four tentacula, the two upper ones ear-shaped, eyes situated near the mouth; dorsal shield semicircular, subcartilaginous, adhering on one side, and covering the branchial cavity.

_Shell._ Nearly round, left margin somewhat reflected; outer lip acute; yellowish horn colored, with brown radiations, and two concentric bands. Inhabits the Indian seas. Thirty-seven species.

Aplysia depilans. A. teremida. A. gigas. A. hassetlii. A. punctata. A. marmorata. A. dolabrifera. A. ascifera. A. petalifera. A. unguifera. A. Limacina. A. Jeachii. A. saviguana. A. fasciata. A. bresili. A. dactycomela. A. protea. A. sorex. A. tigrina. A. maculauta. A. longicauda. A. Kerandrenii. A. lessonii. A. camelus. A. alba. A. Napolitana. A. viridis. A. longicornis. A. ecaudata. A. virescens. A. poliana. A. fusca. A. pleii. A. citrini. A. undata. A. rosea. A. Ferrusacii.

FAMILY VI.

LIMACINA. Five genera.

1. Genus _Limax_. Pl. X.

_Animal._ Cuvier merely mentions that the animal is “furnished with a coriaceous, subrogose shield, with a flat, longitudinal disk beneath; four tentacula retractile, eyes at the tips; orifice for respiration on the right side.”

_Shell._ Ovate oblong, both margins reflected; very thin, diaphanous, slightly wrinkled, of a pale yellow colour. Inhabits the gardens in Britain and France. Five species.

Limax rufus. L. cinerus. L. albus. L. agrestis. L. punctata.

2. Genus _Vitrina_. Pl. X.

_Animal._ Body creeping, elongated, snail shaped, nearly straight; posteriorly separated from the foot, and spirally wound into a shell.

_Shell._ Small, very thin, depressed, terminated above by a very short spire, the last whorl very large; aperture large, rounded oval; the left margin arched, slightly involute. Inhabits dry places of Europe. Three species.

Vitrina parilis. V. dentilis. V. pellucida.

3. Genus _Testacella_. Pl. X.

_Animal._ Body creeping, elongated, snail shaped, having a shell placed on the posterior extremity; four tentacula, the two longest with their eyes at their tips; respiratory organs behind.

_Shell._ Very small, external, ear-shaped, apex absolutely spiral, aperture very large and oval, left edge sharp and rolled inward behind. Inhabits the middle provinces of France. Two species.

Testacella Haliotidea. T. Neritoidea.

4. Genus _Parmacella_. Pl. X.

_Animal._ Body creeping oblong; middle of the back moderately convex, and shield-shaped; hind part in form of a tail, laterally compressed, acute above; shield ovate, fleshy, adhering at its posterior part, free before, enveloping a shell, with a notch in the centre of its right margin; four tentacula, two posterior largest; respiratory organs, under the notch of the shield, placed between the two tentacula of the right side.

_Shell._ Ovate, left margin broad and reflected; right margin reflected at top and acute beneath; very thin and pellucid, of a pale yellowish-brown. Inhabits the gardens of Europe. Two species.

Parmacella Olivieri. P. Cuvierii.

5. Genus _Onchidium_. Pl. X.

_Animal._ Body oblong, creeping, marginated on all sides; head projecting, the lower part with a prominent margin, two retractile, cylindrical tentacula; two auriform appendages, nearly lateral; mouth beneath, destitute of maxillary processes; respiratory orifices distinct, under the extremity of the body.

Destitute of a shell. Inhabits the gardens of Europe. Two species.

Onchidium Typhæ. O. Peronii.

FAMILY VII.

COLIMACEA. Eleven genera.

1. Genus _Helix_. Pl. X.

_Animal._ Of a slightly variable form, the mantle forming at its free edge a kind of ring or thick collar, especially in front, and faintly divided into two lips; foot oval, plane, smooth beneath, inflated and granular below, joined to the visceral club by a narrow peduncle; head sufficiently distinct; anterior tentacula very evident and inflated at top, the posterior very long; the mouth a vertical cleft provided with two labial lobes, a sort of marginal tooth, with a small, oval, lingual club.

_Shell._ The name Helix was given to this genus from the spiral shape of the shell, which varies much in form, but generally globular, and ventricose, conoid but never turriculated; summit generally obtuse, aperture varying much in size, sometimes very large, sometimes small, always regulated by the turn of the spire; oval, semilunar, more wide than long, edges disunited, entering little into the interior; right lip or margin thickened or reflected inwards. Inhabits the groves and woods both of America and Europe. Two hundred and three species.

Helix vesicalis. H. gigantea. H. polyzonalis. H. monozonalis. H. pulla. H. lineolata. H. mutata. H. pomatia. H. aspersa. H. vermiculata. H. Alonensis. H. vesicolor. H. naticoides. H. picta. H. galactites. H. cepa. H. heteroclites. H. discolor. H. lactea. H. zonaria. H. guttata. H. Madagascarensis. H. Javanica. H. Peruviana. H. simplex. H. cidaris. H. citrina. H. algira. H. verticellus. H. olivetorum. H. hæmastoma. H. melanotragus. H. extensa. H. lucana. H. globulus. H. melanostoma. H. cœlatura. H. microstoma. H. maculsa. H. Richardi. H. Bonplandii. H. planulata. H. labrella. H. unguina. H. pellis-serpentis. H. senegalensis. H. unidentata. H. fructicum. H. neglecta. H. crespitum. H. ericetorum. H. intersecta. H. Carthusianella. H. diaphana. H. concolor. H. velutina. H. obvuluta. H. Cookiana. H. pileus. H. papilla. H. punctifera. H. plicatula. H. planorbella. H. scabra. H. cariosa. H. crenulata. H. planorbula. H. macularia. H. planospira. H. Barbadensis. H. sinuata. H. hippocastanum. H. bidentalis. H. argilacea. H. vittata. H. arbustorum. H. candidissima. H. memoralis. H. Hortensis. H. sylvatica. H. pisana. H. splendida. H. serpentina. H. niciensis. H. variabilis. H. auriculata. H. turgidula. H. helicella. H. zonula. H. tridentata. H. septemvalva. H. monodan. H. fraterna. H. coniformis. H. concamerata. H. nigrescens. H. Tripolitana. H. Sayii. H. globulosa. H. Caffra. H. conformis. H. prunum. H. Pouzolzii. H. contusa. H. bicarinata. H. vitrinoides. H. maritima. H. strigata. H. muralis. H. rugosa. H. cornea. H. liquifera. H. incarnata. H. cinctella. H. cellaria. H. Gaymardii. H. nitidia. H. plebuim. H. personata. H. hispidia. H. rotundata. H. apicina. H. striata. H. conspurcata. H. conica. H. conoidea. H. pulchella. H. formosa. H. orbiculata. H. squamosa. H. tectiformis. H. Madeirensis. H. unbeculata. H. deformis. H. Nicæensis. H. meridionalis. H. melitensis. H. circumornata. H. gronosa. H. Lima. H. dentiens. H. parilis. H. imperator. H. zodiaca. H. concisa. H. pellicuta. H. strobilus. H. alanda. H. carina. H. Bulverii. H. pileolus. H. vipartita. H. sinistrorsa. H. fibula. H. supplicata. H. Porto-santara. H. punctulata. H. exalbida.

· · · · ·

H. Mitchelliana.* H. Vancouverensis.* H. Caroliniensis.* H. Nuttaliana.* H. Columbiana.* H. hirsuta.* H. perspectiva.* H. lineata.* H. multilineata.* H. appressa.* H. palliata.* H. Californiensis.* H. Townsendiana.* H. Nichliniana.* H. Oregonensis.* H. magnifica.* H. profunda.* H. albolabris.* H. alternata.* H. irrorata.* H. inorata.* H. indentata.* H. inflecta.* H. clausa.* H. obstricta.* H. elevata.* H. interna.* H. chersina.* H. gularis.* H. ligera.* H. solitaria.* H. jejuna.* H. concava.* H. fallax.* H. egena.* H. arboreus.* H. glaphyra.* H. Thyroides.* H. labyrinthica.* H. major.* H. Pennsylvanica.* H. subglobosa.* H. Zaleta* H. dentifera.* H. delabata.*

2. Genus _Carocolla_. Pl. X.

The _Animal_ of this and the following genera of this family are precisely the same as in Helix.

_Shell._ Orbicular, more or less convex or conoidal above; the circumference or periphery angulated or keeled; aperture transverse, contiguous to the axis of the shell; the right margin or lip subangular, often toothed or plaited beneath. Inhabits dry situations in Europe and America. Twenty-two species.

Carocolla acutistima. C. albilabris. C. angistoma. C. labyrinthus. C. lucerna. C. inflata. C. hispidula. C. Gaulteriana. C. albella. C. bicolor. C. Mauritiana. C. Madagascarensis. C. marginata. C. lychnuchus. C. planata. C. planaria. C. lapicida. C. elegans.

· · · · ·

C. Hydiana.* C. helicoides* (new species) _Lea_. C. grata.* C. Spinosa* (new species) _Lea_.

3. Genus _Achatina_. Pl. X.

_Animal._ See Helix.

_Shell._ Variable in form, but generally subturriculated, oval or oblong, aperture entire, the right lip sharp, never reflected, columella smooth, of which the anterior extremity is always open and truncated. Inhabits South America. Twenty-four species.

Achatina perdix. A. immaculata. A. acuta. A. Mauritania. A. ustulata. A. virginea. A. Marminii. A. fusco-lineata. A. columnaria. A. acicula. A. zebra. A. purpurea. A. bicarinata. A. castanea. A. vexillum. A. Priamus. A. Peruviana. A. albo-lineata. A. fulminea. A. folliculus. A. oleacea.

· · · · ·

A. glans.* A. Vanuxemensis.* A. solida.*

4. Genus _Anostoma_. Pl. X.

_Animal._ See Helix.

_Shell._ Somewhat extraordinary in its formation, orbicular, the spire convex and obtuse, aperture round, dentated grinning, turned upwards to the side of the spire, margin of the lip reflected. Lakes in America and the Sandwich Islands. Three species.

Anostoma dentata. Anostoma depressa.

· · · · ·

A. globosa.*

5. Genus _Helicina_. Pl. X.

_Animal._ See Helix.

_Shell._ Terrestrial, distinguished only from the Helix by its columella being transverse callous; much depressed and diminished in thickness at the lower part, subliglobular, imperforate; aperture entire, demioval, margin acute, forming an angle at the lower base of the right lip; operculum corneous. Inhabits groves in Europe. Nineteen species.

Helicina neritella. H. rhodostoma. H. striata. H. fasciata. H. virida. H. pulchella. H. substriata. H. Braziliensis. H. costata. H. aurantia. H. major. H. minima. H. submarginata. H. unifasciata. H. Brownii. H. depressa. H. aureola. H. orbiculata. H. Tankervillii.

6. Genus _Pupa_. Pl. X.

_Animal._ See Helix.

_Shell._ Cylindrical, generally thick; aperture irregular, semi-ovate, rounded, and subangulated beneath; margins of outer lip nearly equal and reflected outwardly, unconnected at their upper parts; the plait of the columella interposed between them. Most frequently found in moss in Europe and America. Forty species.

Pupa numia. P. uva. P. sulcata. P. candida. P. labrossa. P. fusus. P. tridentata. P. fasciolata. P. zebra. P. unicarinata. P. maculosa. P. clavulata. P. ovularis. P. Germanica. P. cinerea. P. tridens. P. quadridens. P. polyodon. P. variabilis. P. frumentum. P. secale. P. avena. P. granum. P. fragilis. P. dolium. P. umbilicata. P. muscorum. P. angilicus. P. rufescens. P. edontulis. P. odontostoma. P. petiveriana. P. dentata.

· · · · ·

P. contracta.* P. rupicola.* P. exigua.* P. armifera.* P. fallax.* P. ovata* P. pentadon.*

7. Genus _Clausilia_. Pl. X.

_Animal._ See Helix.

_Shell._ Cylindrical, generally fusiform; summit obtuse, the last whorl smaller than the preceding; aperture irregular, rounded, oval; margin united, and externally reflected. Inhabits dry situations both in Europe and America. Fifteen species.

Clausilia torticollis. C. truncatula. C. retusa. C. costulata. C. corrugata. C. inflata. C. Mediterranea. C. denticulata. C. collaris. C. papillaris. C. plicatula. C. rugosa. C. gracilis. C. chrysalis.

· · · · ·

C. teres.*

8. Genus _Bulimus_. Pl. X.

_Animals_ of this genus in formation are precisely as the Helix; they are, however, oviparous, producing eggs with the shell containing the animal perfectly matured; they are frequently as large as a pigeon’s egg.

_Shell._ Oval, sometimes turriculated, oblong; the summit of the spire obtuse, and the last whorl larger than all the others together; aperture oblong, oval, edge disunited; in adults the lip much reflected; columella smooth, with an inflection in the middle, the base entire, not channeled. Inhabits mountainous situations in Europe and America; some beautiful specimens have been found in the woods of Ohio. Sixty-three species.

Bulimus ovatus. B. hæmastomus. B. gallina. B. sultana. B. zigzag. B. multifasciatus. B. Bengalensis. B. Caribæorum. B. octonus. B. terebraster. B. undatus. B. Richii. B. inversus. B. citrinus. B. sultanus. B. Pythogaster. B. ovoideus. B. interruptus. B. Peruvianus. B. Favannii. B. Kambeul. B. papyraceus. B. calcareus. B. decollatus. B. Lyonetianus. B. inflatus. B. radiatus. B. fragilis. B. Guadalupensis. B. Mexicanus. B. articulatus. B. acutus. B. scobinatus. B. planidens. B. ventricosus. B. montanus. B. hordaceus. B. lubricus. B. iostoma. B. geniostoma. B. odontostoma. B. formosus. B. Listeri. B. Kingii. B. Dufresnii. B. pulcher. B. maugeri. B. lævis. B. auris leporis. B. vexillum.

· · · · ·

B. glandiformis.* B. parvus.* B. virgo.* B. gracilis.* B. Gibbonius.* B. multilatus.* B. maculatus.* B. Pealianus.* B. lacteus.* B. decoratus.* B. Columbianus.* B. multilineatus.* B. corneus.*

9. Genus _Succinea_. Pl. X.

_Animal._ See Helix.

_Shell._ Terrestrial, very thin, pellucid, ovate oblong, with a conical, pointed spire, formed of only one or two whorls; aperture very large and oval, edges disunited; right edge always acute, the left arched, formed by a smooth attenuated columella. The shells of this genus never having their lip thickened or reflected, distinguish them from those of the genus Bulimus, to which they bear a strong resemblance. Inhabits the sides of ditches and lakes, both in Europe and America. Seven species.

Succinea cuculata. S. amphibia. S. rubescens. S. oblonga. S. patula. S. pellucida.

· · · · ·

S. aperta.*

10. Genus _Auricula_. Pl. X.

_Animal._ See Helix.

_Shell._ Solid, thick, and smooth, oval, oblong spire very obtuse, aperture entire, enlarged, ear-shaped, much contracted behind; edges not united, right lip thick and generally reflected outwardly; the left or columella with one or more teeth or callous plaits. This genus derives its name from its resemblance to the ears of certain animals. It is a land shell found chiefly in the East and West India Islands. Sixteen species.

Auricula Midæ. A. Judæ. A. sileni. A. leporis. A. felis. A. Dombeiana. A. nitens. A. angiostoma. A. scarabæus. A. bovina. A. caprella. A. myosotis. A. minima. A. coniformis. A. monill. A. labrella.

11. Genus _Cyclostoma_. Pl. X.

_Animal._ See Helix.

_Shell._ Terrestrial, distinguished from the preceding genera by a perfectly round aperture, reflected lip, and horny operculum, summit papillose; left edge having its origin very detached from the spire. Inhabits the East Indies. A few species are found in America. Thirty-eight species.

Cyclostoma planorbula. C. volvulus. C. carinata. C. sulcata. C. unicarinata. C. rugosa. C. labeo. C. interrupta. C. ambigua. C. semilabris. C. tricarinata. C. obsoleta. C. patulum. C. truncatum, C. pulchrum. C. Jamaicense. C. lineolata. C. elongatum. C. mirabile. C. orbella. C. aurantium. C. flavula. C. fasciata. C. mumia. C. quarternata. C. ferruginea. C. decussata. C. mammillaris. C. maculatum. C. ligata. C. elegans. C. tortum. C. mirabile.

· · · · ·

C. maculata.* C. Popayana.* C. lapidaria.* C. marginata.* C. dentata.*

FAMILY VIII.

LYMNACEA. Three genera.

1. Genus _Lymnea_. Pl. X.

_Animal._ See Helix.

_Shell._ Aquatic, oval, sometimes turreted; spire produced, thin, smooth, edges disunited, the left with a very oblique plait rising on the columella, forming an oval aperture, destitute of an operculum. Inhabits the ponds of America and Europe. Thirty-three species.

Lymnea columnaris. L. stagnelis. L. palustris. L. auricularia. L. ovata. L. minuta. L. luteola. L. acuminata. L. intermedia. L. leucostoma. L. peregra.

· · · · ·

L. rubiginosus.* L. solida.* L. Virginiana.* L. Emmoniensis.* L. lessoni.* L. apacina.* L. catascopium.* L. columella.* L. elongatus.* L. reflexus.* L. appressus.* L. elodes.* L. limosa.* L. lapidaria.* L. dissimilis.* L. ponderosa.* L. integra.* L. porata.* L. lustrica.* L. grana.* L. subglobosa.*

2. Genus _Physa_. Pl. X.

_Animal._ See Helix.

_Shell._ General sinistral, oval, oblong, or globular, very smooth, spire prominent, aperture oval, contracted posteriorly, right edge sharp, columella twisting obliquely, and enlarging to join itself to the anterior part of the margin, the whorls turning to the left hand gives this shell the appellation of heterostrophe. Inhabits the ditches of America and Europe. Ten species.

Physa fontinalis. P. hypnorum. P. subopaca.

· · · · ·

P. castanea.* P. decisa.* P. elongata.* P. aurea.* P. gyrina.* P. heterostropha.* P. ancillaria.*

3. Genus _Planorbis_. Pl. X.

_Animal._ See Helix.

_Shell._ Discoid, spire depressed, or involuted almost in the same vertical plane, causing the shell to be depressed on each side, aperture oblong, luniform, axis remote, margin not reflected; no operculum. Inhabits the lakes of America and Europe. Twenty-two species.

Planorbis cornu-arietis. P. corneus. P. spirorbis. P. hispidus. P. orientalis. P. carinatus. P. lutescens. P. nitidus. P. angulatus. P. deformis. P. imbricatus. P. contortus. P. vortex.

· · · · ·

P. lens.* P. glabratus.* P. armigerus.* P. parallellus.* P. exacuous.* P. campanulatus.* P. trivolvis.* P. bicarinatus.* P. parvus.*

FAMILY IX.

MELANIANA. Three genera.

1. Genus _Melania_. Pl. X.

_Animal._ See Helix.

_Shell._ Turreted; aperture entire, spire slightly pointed, margin of the whorls often surmounted by spires, columella smooth and arched, closed by a thin horn-like operculum; this is a fluviatile shell, often covered by a thick epidermis. Inhabits the rivers of India. Many fine species are found in America. Fifty-four species.

Melania inquinata. M. asperata. M. spinolusa. M. gronifera. M. aurita. M. lineolata. M. trunculata. M. carinefera. M. truncata. M. coarctata. M. punctata. M. subulata. M. Helvetica. M. lineata. M. Byronensis. M. sulcata. M. lævigata. M. clavis. M. decollata. M. amarula. M. thiarella. M. fasciolata. M. lævissima. M. corrugata.

· · · · ·

M. Troostiana.* M. plicifera.* M. Sayii.* M. elevata.* M. armigera.* M. multilineata.* M. proxima.* M. Hydeii.* M. salebrosa.* M. bitaeniata.* M. lema.* M. nassula.* M. trochiformis.* M. elevata.* M. laqueata.* M. semicarinata.* M. subularis* (_Lea_). M. acuta.* „ M. plicata.* M. inflata.* N. conica.* M. catenaria.* M. simplex.* M. excurta.* M. annulifera.* M. pyrenella.* M. coma.* M. alveare.* M. cylindracea.* M. vestita.* M. caniculata.* M. Virginica.* M. tuberculata* (_Lea_). M. elongata.* „

2. Genus _Pirena_. Pl. X.

_Animal._ Much elongated, mantle prolonged into a canal at the left side, but without distinct tube; foot short, oval, with an anterior marginal furrow; head terminated by a depressed proboscidiform muzzle; tentacula very distant, thickly annulated, dilated in the inferior half of their length, and having the eyes at the summit of this dilation; mouth a terminal and vertical slit, without labial tooth, and with a very small tongue; a single long and narrow branchia.

_Shell._ Distinguished from the preceding genus by having a sinus at the base, and another at the summit; turreted; aperture longitudinal, right lip sharp, base of the columella inclined to the right. Inhabits the rivers of India and Africa. One species is found in America. Six species.

Pirena terebralis. P. cancellata. P. aurita. P. spinosa. P. granulosa.

· · · · ·

P. scalariformis.*

3. Genus _Melanopsis_. Pl. X.

_Animal._ As preceding genus.

_Shell._ The Melanopsis is distinguished from the Melanaia, by the columella being callous in the upper part, and the base truncated as in the Achatina, and differs from the Pirena in having only a sinus or widened opening at the base of the shell; aperture covered by a horny operculum. Inhabits the rivers of the Archipelago. Three species.

Melanopsis costata. M. lævigata. M. prærosa.

FAMILY X.

PERISTOMIANA. Three genera.

1. Genus _Valvata_. Pl. X.

_Animal._ See Helix.

_Shell._ Found only in fresh water; subdiscoid or conoid, umbilicated, spiral, whorls, rounded; angular at the summit; aperture round, not modified by the penultimate whorl; the margins sharp and united; operculum orbicular and horny. Inhabits the rivers of Europe and America. Three species.

Valvata piscinalis.

· · · · ·

V. arcnifera.* (_Lea_.) V. tricarinata.*

2. Genus _Paludina_. Pl. X.

_Animal._ See Helix.

_Shell._ Generally found in fresh water, though some species have been found where it is salt; conoid covered with a greenish epidermis; the whorls rounded or convex, spiral cavity modified by the last whorl; aperture rounded, oval, oblong, angular at the summit; margins united, acute, never reflected outwards; operculum orbicular and horny. Inhabits the rivers of America and Europe. Thirty-one species.

Paludina vivipara. P. Bengalensis. P. viridis. P. Francesii. P. achatina. P. Australis. P. impura. P. muriatica.

· · · · · P. sinistrosa.* P. Nuttaliana.* P. virens.* P. pallida.* P. subcarinata.* P. genicula.* P. magnifica.* P. limosa.* P. subglobosa.* P. lapidaria.* P. Virginica.* P. hyalina.* P. unicolor.* P. nuclea.* P. decisa.* P. fuscus.* P. dissimilis.* P. ponderosa.* P. integra.* P. porata.* P. lustrica.* P. grana.* P. Nickliniana.*

3. Genus _Ampullaria_. Pl. X.

_Animal._ Inflated, globular, spiral; foot oval, with a transverse furrow at its anterior edge; head wide; tentacula superior, very long, conical, and pointed; eyes situated at their external base, and supported upon a very apparent peduncle; mouth vertical, situated between two lips disposed in form of a horse-shoe and forming a kind of muzzle; no superior tooth; a bristly lingual band, but not prolonged into the abdominal cavity; a very large respiratory cavity, divided in two by an incomplete horizontal partition.

Animals of this genus are oviparous; producing an egg nearly as large as that of a pigeon, in which is found the young animal complete, and in a perfectly formed shell.

_Shell._ This genus appears to partake of the characteristics, both of the Paludina and the Natica, being fluviatile and frequently attaining a large size; spire very short, the last whorl much larger than all the others together; globular, very ventricose, umbilicus small, forming a compressed funnel-shaped aperture, without interior callosity; aperture longer than broad, with margins united; columellar lip thickened, projecting and reflected over the umbilicus; operculum horny. Inhabits the rivers of Europe. Thirteen species.

Ampullaria vivipara. A. fasciata. A. rugosa. A. canaliculata. A. effusa. A. virens. A. avellana. A. fragilis. A. Guinica. A. carinata. A. intorta. A. conica.

· · · · ·

A. Pealiana.*

FAMILY XI.

NERITACEA. Four genera.

1. Genus _Neritina_. Pl. X.

_Animal._ Globular; foot circular, thick, without a furrow anteriorly, or a lobe for the operculum posteriorly, with a bipartite columellar muscle; conical tentacula; eyes subpedunculate at their external side; mouth without labial tooth, but with a denticulated tongue prolonged into the visceral cavity; a single large pectiniform branchia.

_Shell._ This genus was formerly classed with the Nerita, which in form it much resembles, but from the circumstance of the latter inhabiting the sea, and Neritinæ fresh water, it now forms a separate genus. Thin, smooth, or finely striated, in all the species known, the right side of the aperture does not possess any crenulations or teeth; the operculum is provided with a lateral tooth on one side. Some species are armed with spines; aperture semicircular; left margin smooth and sharp; spire imperfect, generally dissolved by the animal. Inhabits the fresh water rivers of Europe. Twenty-seven species.

Neritina perversa. N. pulligera. N. dubia. N. zebra. N. zigzag. N. gagates. N. lugubris. N. lineolata. N. fasciata. N. semiconica. N. strigilata. N. meleagris. N. virginea. N. fluviatilis. N. viridis. N. Bætica. N. careosa. N. caffra. N. Domingensis. N. auriculata. N. crepidularia. N. brevispina. N. Smithii. N. spinosa. N. Oweni. N. pulchella. N. corona.

2. Genus _Nerita_. Pl. X.

_Animal._ See Neritina.

_Shell._ Marine, but never spined, solid, semiglobular, flattened beneath, not imbilicated; aperture large, entire, semilunar, the external margin much hollowed; the columella sharp and often dentated, operculum horny, subspiral, with a projecting tooth. Inhabits the seas of S. America and W. Indies. Twenty species.

Nurita exuvia. N. textilis. N. undata. N. peloronta. N. chlorostoma. N. atrata. N. polita. N. albicella. N. chamæleon. N. versicolor. N. lineata. N. scabricosta. N. plicata. N. tassellata. N. signata. N. ornata. N. Australis. N. rudis. N. Ascensionis. N. Malaccensis.

3. Genus _Navicella_. Pl. X.

_Animal._ Oval, not spiral, foot elliptical, very large, with a thin subpapillary edge, advanced rather anteriorly, without marginal furrow, but attached on each side to the visceral mass in all its posterior portion so as to form a sort of cavity open transversely behind; head very broad and semilunate; tentacula conical, contractile and distant; eyes subpedunculated at the external root of the tentacula; mouth large and longitudinal.

_Shell._ Fluviatile, elliptical, or oblong, convex above, summit straight, depressed to the margin, concave beneath; no columella; the columellar edge replaced by a sharp partition, covering part of the aperture; a sinus at its left extremity; muscular impression horse-shoe shaped, open in front and interrupted behind; thin, calcareous operculum, with a subulate, lateral tooth adhering to the posterior margin. Inhabits rivers in the Isle of France. Four species.

Navicella elliptica. N. tesselatus. N. lineata. N. porcelanica.

4. Genera _Natica_. Pl. XI.

_Animal._ Oval, subspiral; foot profoundly and transversely bilobed anteriorly, and having a horny or calcareous operculum; head provided with long setaceous tentacula, flat, and auriculated at the base; eyes sessile at the external side of the root of the tentacula; mouth armed with a labial tooth.

_Shell._ Marine, distinguished from the Nerita by having no teeth, and having an umbilicus modified by a callosity; very smooth and glossy; no epidermis; spire evident, but low; columellar edge not toothed; right edge without teeth; operculum calcareous and smooth, semi-spiral, with concentrical ribs, fitting a groove on the columella. Inhabits the W. Indian Ocean and American seas. Thirty-six species.

Natica ampullaria. N. plumbea. N. conica. N. aurantia. N. melanostoma. N. mamilla. N. mamillaris. N. albumen. N. glaucina. N. canrena. N. cruentata. N. millepunctata. N. vitellus. N. helvacca. N. collaria. N. monilifera. N. labrella. N. unifasciata. N. lineata. N. fulminata. N. maculosa. N. vitata. N. castanea. N. arachnoidea. N. zebra. N. Marochiensis. N. Javanica. N. zonaria. N. cancellata. N. patula. N. duplicata. N. intricata. N. glabrata. N. Chinensis. N. rufa.

· · · · · N. consolidata.* N. duplicata.* N. heros.* N. pusilla.* N. triseriata.* N. rugosa.*

FAMILY XII.

JANTHINEA. One genus.

1. Genus _Janthina_. Pl. XI.

_Animal._ Of oval form, spiral, provided with a circular concave foot, accompanied with a vesicular subcartilaginous mass, and natatory appendages on each side; head very thick; tentacula scarcely at all contractile; eyes situated beneath the extremity of long peduncles placed at the external side of the tentacula, and appearing to form a part of them; mouth at the extremity of a very thick proboscidiform muzzle, between two vertical, subcartilaginous lips furnished with sharp spines.

_Shell._ Of a beautiful violet colour, found in numbers floating on the surface of the ocean, suspended by a vesicular appendage which gives a rich purple stain. Extremely thin and fragile, spire low, lateral, pointed, with subcarinated whorls; aperture large, subangular, modified by the last whorl of the spire, edges disunited, the left formed by the columella, which is straight, continuing beyond the base, right edge sharp, with a sinus in the middle. Inhabits the Atlantic Ocean. Three species.

Janthina naticoides. J. communis. J. exigua.

FAMILY XIII.

MACROSTOMIANA. Four genera.

1. Genus _Sigaretus_. Pl. XI.

_Animal._ Body oval, flat beneath; edges of the mantle vertical, thin, extending beyond the body in all directions, sloped anteriorly; the mantle itself dilated superiorly.

_Shell._ More or less thick, internal, without colour, much depressed, with a short, low, lateral spire; left edge of the aperture trenchant; two lateral muscular impressions very distant. Inhabits the Indian Ocean. Two species are found in S. America. Six species.

Sigaretus convexus. S. Haliotoideus. S. cancellatus. S. lævigatus.

· · · · ·

S. perspectivus.* S. maculatus.*

2. Genus _Stomatella_. Pl. XI.

_Animal._ Unknown.

_Shell._ Distinguished from the Stomatia by being destitute of a transverse rib, orbicular, oblong ear-shaped, imperforate; aperture entire, large, sublongitudinal; right lip effuse, dilated, open. Inhabits the Indian Ocean. Five species.

Stomatella imbricata. S. rubra. S. sulcifera. S. auricula. S. planulata.

3. Genus _Stomatia_. Pl. XI.

_Animal._ Unknown.

_Shell._ Ear-shaped, imperforate, spire prominent; aperture entire, large, oblong; right margin and columella equally raised; a transverse and tuberculated rib on the back. Inhabits the Indian Ocean. Two species.

Stomatia phymotis. S. obscurata.

4. Genus _Haliotis_. Pl. XI.

_Animal._ Body oval, much depressed, slightly spiral posteriorly, provided with a large foot doubly fringed at its circumference; head depressed; tentacula a little flattened; eyes at the summit of prismatic peduncles situated at the external side of the tentacula; mantle very thin, deeply slit at the left side; the two lobes pointed, and forming by their union a kind of canal to conduct water into the branchial cavity, and including two very long unequal branchial combs.

_Shell._ This beautiful genus derives its name from its resemblance to the human ear. The exterior, tuberculated, and generally loaded with marine substances, giving it an uncouth appearance, but its iridescent interior forms a magnificent contrast; it is pearly, with all the hues of the rainbow, recurving very depressed, oval, spire very small, sometimes eroded, almost posterior, aperture as large as the shell, with margins reflected inwards, the right sharp, left flat, and enlarged; disk pierced with holes, disposed in a line parallel to and near the left margin, the last commencing with a notch. These holes formed by the animal, as it increases the size of the shell, to admit the passage of a short syphon; they adhere to rocks, and are removed with much difficulty. Inhabits the sea at Molucca. Nineteen species.

Haliotis tuberculata. H. striata. H. asinina. H. glabia. H. lamellosa. H. unilateralis. H. rugosa. H. canaliculata. H. tricostalis. H. dubia. H. iris. H. tubifera. H. excavata. H. Australis. H. Midæ. H. rubra. H. tricostata. H. corrugata. H. Mariæ.

FAMILY XIV.

PLICACEA. Two genera.

1. Genus _Tornatella_. Pl. XI.

_Animal._ Body oval, subspiral; foot divided into two heels by a wide transverse furrow; head provided with two vertical cylindrical tentacula, having the eyes placed sessilely upon their interior side.