Chapter XXXVII: Introduction: Division I. Ecardines--External (3)

[96] I succeeded in hatching out eggs of _Helix aspersa_, during the very warm summer of 1893, in 17 days.

[97] _Nachr. Deutsch. Malak. Gesell._ xx. p. 146.

[98] Raymond, _Nautilus_, iv. p. 6.

[99] Quoted by Oehlert, _Rév. Sc._ xxxviii. p. 701.

[100] _Animal Life, Intern. Scientif. Ser._ ed. 1, p. 395.

[101] _Zoologist_, 1886, p. 491.

[102] Thomas, quoted by Jeffreys, _Brit. Conch._ i. p. 30.

[103] _Journ. of Conch._ iv. p. 117.

[104] Rev. L. Jenyns, _Observations in Nat. Hist._ p. 318.

[105] _Id. ib._ p. 319.

[106] Further detailed examples will be found in Kew, _The dispersal of Shells_, pp. 5–26.

[107] _P. Z. S._ 1888, p. 358.

[108] W. A. Gain, _Naturalist_, 1889, p. 58.

[109] _Das Wetter_, Dec. 1892. Another case is recorded in _Amer. Nat._ iii. p. 556.

[110] _Zoologist_, x. p. 3430.

[111] _Science Gossip_, 1888, p. 281.

[112] Lecoq, _Journ. de Conch._ ii. p. 146.

[113] Bouchard-Chantereaux, _Ann. Sci. Nat. Zool._ (4) xvi. (1861) p. 197.

[114] Forel, _Ann. Sci. Nat._ (3) xx. p. 576; Bretonnière, _Comptes Rendus_, cvii. p. 566.

[115] Brit. Mus. Collection.

[116] Thomas, quoted by Récluz in _Journ. de Conch._ vii. 1858, p. 178.

[117] _Nat. Hist. of Ceylon_, p. 382. See also T. L. Taylor, _Rep. Brit. Ass._ for 1848, p. 82.

[118] Dr. R. E. Grant, _Edinb. Phil. Journ._ xiv. p. 188.

[119] _Rep. Brit. Ass._ for 1848, p. 80. The statement is confirmed by Rossmässler.

[120] _Journ. of Conch._ iv. p. 118.

[121] _Zoologist_, 1887, p. 29.

[122] _Arch. Zool. Exp. Gén._ (2) v. p. 459 f.

[123] _Journ. of Conch._ iii. p. 277; compare W. M. Webb, _Zoologist_, 1893, p. 281.

[124] _Bull. Mus. Comp. Zool. Harv._ iv. p. 85.

[125] Erjavec, _Nachr. Deutsch. Malak. Gesell._ 1885, p. 88.

[126] Crosse, _Journ. de Conch._ (3) xiv. (1874) p. 223.

[127] C. Wright, _Zoologist_, 1869, p. 1700.

[128] W. V. Legge, _Zoologist_, 1866, p. 190.

[129] Blackwall, _Researches_, p. 139.

[130] Barrow, _Travels in South Africa_, ii. p. 67.

[131] _Loch Creran_, p. 102.

[132] Cordeaux, _Zoologist_, 1873, p. 3396.

[133] _Amer. Nat._ xii. p. 695; _Science Gossip_, 1865, p. 79.

[134] _Journ. Trent. N. H. Soc._ 1887, p. 58.

[135] _Ann. Nat. Hist._ iii. 1893, pp. 238, 239.

[136] _Rev. Nat. Sc. Ouest_, 1891, p. 261.

[137] Petit de la Saussaye, _Journ. de Conch._ iii. p. 97 f.

[138] J. W. Williams, _Science Gossip_, 1889, p. 280.

[139] Noack, _Zool. JB._ ii. p. 254.

[140] _La Nature_, xv. (2) p. 46.

[141] François, _Arch. Zool. Exp. Gén._ (2) ix. p. 240.

[142] A. Lang, _Ber. Naturf. Ges. Freib._ vi. 1892, p. 81.

[143] A. P. Thomas, _Q. J. Micr. Sc._ N. S. xxiii. (1883) p. 99.

[144] H. Woodward, _P. Z. S._ 1886, p. 176.

[145] W. E. Collinge, _Zoologist_, 1890, p. 467.

[146] _Proc. Linn. Soc. N. S. Wales_, ix. p. 944.

[147] _Zoologist_, xviii. (1860) p. 7136.

[148] A. Adams, _Samarang_, vol. ii. _Zoology_, p. 357.

[149] In Thomson’s _British New Guinea_, p. 283.

[150] _Animal Life_, p. 395. It should be mentioned that Von Möllendorff (_Ber. Senck. Ges._ 1890, p. 198) ridicules the whole theory.

[151] Von Martens, _SB. Nat. Fr. Berl._ 1891, p. 83.

[152] Von Martens, _ibid._ 1887, p. 183.

[153] _SB. Nat. Gesell. Leipz._ xiii.-xiv. p. 45.

[154] Garstang, _Journ. Mar. Biol. Ass._ N. S. i. p. 432; Giard, _Bull. Sci. Fr. Belg._ 1888, p. 502 f.

[155] _Nautilus_, vi. 1892, p. 90.

[156] R. F. Scharff, _Sci. Trans. R. Dubl. Soc._ (2) iv. p. 553 f.

[157] _Q. Journ. Micr. Sci._ N. S. xxxi. (1890) p. 41 f.

[158] A detailed account is given in _Proc. Liverp. Biol. Soc._ iv. (1890) pp. 150–163.

[159] _Journ. Mar. Biol. Ass._ N. S. i. p. 418 f.

[160] Garstang, _Conchologist_, ii. p. 49.

[161] Hecht, _Comptes Rendus_, cxv. p. 746.

[162] _Conchologist_, ii. p. 130.

[163] Described as a _Cypraea_, but no doubt an _Ovula_ or _Pedicularia_: _CB. Bakt. Par._ v. p. 543.

[164] Von Graff, _Z. wiss. Zool_ xxv. p. 124.

[165] _Proc. Amer. Phil. Soc._ xxv. p. 231.

[166] _Ergeb. naturw. Forsch. Ceylon_, abstr. in _Journ. Roy. Micr. Soc._ (2) vi. p. 412.

[167] _Voyage of the Samarang_, Moll. p. 69, Pl. xi. f. 1; p. 47, Pl. xvii. f. 5.

[168] E. A. Smith, _Ann. Mag. Nat. Hist._ (6) iii. p. 270.

[169] _Journ. de Conch._ (3) xxix. p. 101.

[170] _Zool. Jahrb. Abth. f. Syst._ v. p. 619.

[171] See especially Semper, _Animal Life_, Ed. 1, p. 351.

[172] Gould, _Moll. of U.S. expl. exped._ 1852, p. 207 (_St. acicula_, from Fiji).

[173] Stimpson, _Proc. Bost. Soc. N. H._ vi. 1858, p. 308.

[174] Pidgeon, _Nature_, xxxix. p. 127.

[175] W. Anderson Smith, _Loch Creran_, p. 46.

[176] Smart, _Journal of Conch._ v. p. 152.

[177] _Animal Life_, p. 351.

[178] _Journ. of Conch._ vi. 1891, p. 399.

[179] _Ann. Mag. N. H._ (6) vii. p. 276.

[180] Stimpson, quoted by Jeffrey’s _Brit. Conch._ ii. 194.

[181] Stimpson, _Journ. Bost. Soc. N. H._ vi. 1857, p. 48.

[182] E. H. Matthews, _Conchologist_, ii. p. 144.

[183] Thus _Limnaea involuta_, which is almost universally regarded as a good and distinct species, has been held to be no more than a variety of _L. peregra_ produced by locality; see _Zoologist_, 1889, p. 154.

[184] J. W. Taylor, _Journ. of Conch._ v. p. 289, an interesting article, with many useful references.

[185] Möbius, _Report on ‘Pommerania’ Exped._ pp. 138–141.

[186] _Journ. de Conchyl._ xxiii. 1875, p. 105.

[187] J. W. Taylor _ut sup._ p. 300.

[188] _Sci. Trans. R. Dubl. Soc._ (2) iv. p. 555.

[189] J. S. Gibbons, _Journ. of Conch._ ii. p. 129.

[190] C. H. Morris, _ibid._ vii. p. 191.

[191] F. M. Hele, _ibid._ iv. p. 93.

[192] T. D. A. Cockerell, _Science Gossip_, 1887, p. 67.

[193] J. G. Jeffreys, _British Conchology_, vol. i. p. 214.

[194] _Journ. of Conch._ vi. p. 123.

[195] _Phil. Trans._ 1889, vol. 180 B, p. 207. A somewhat similar case (the celebrated Steinheim series of _Planorbis_) is dealt with by Hilgendorf, _MB. Akad. Berl._ 1866, p. 474; and Hyatt, _Proc. Amer. Ass. Sc._ xxix. p. 527.

[196] J. B. Bridgman, _Quart. Journ. Conch._ i. p. 70.

[197] W. C. Hey, _Journ. of Conch._ iii. p. 268.

[198] _Zool. Anz._ xiii. p. 662.

[199] J. Madison, _Journ. of Conch._ v. p. 260.

[200] _Quart. Journ. Conch._ i. 339.

[201] Whitfield, _Bull. Amer. Mus. N. H._ i. p. 29.

[202] _Amer. Nat._ xiv. p. 51.

[203] _Animal Life_, Ed. 1, p. 160 f.

[204] _Conch. Syst._ ii. p. 262 _n._

[205] P. L. Simmonds, _Commercial Products of the Sea_, p. 278.

[206] _Benderloch_, p. 118.

[207] C. Hedley in J. P. Thomson, _Brit. New Guinea_, p. 283.

[208] Most of the above facts are derived from a study of a collection of native implements, weapons, ornaments, etc., in the Antiquarian Museum at Cambridge.

[209] Thurston, _Notes on the Pearl and Chank Fisheries_, Madras, 1890.

[210] See in particular, P. L. Simmonds, _The Commercial Products of the Sea_.

[211] H. Friend, _Field Club_, iv. 1893, p. 100.

[212] _Nature_, xxxi. 1885, p. 492.

[213] W. Anderson Smith, _Benderloch_, p. 173.

[214] Dominique, _Feuill. Nat._ xviii. p. 22.

[215] SB. _Nat. Fr. Berl._ 1889, p. 197.

[216] A. Adams, _Voyage of the ‘Samarang,’_ ii. p. 308.

[217] Much information has been derived, on this subject, from Bertram’s _Harvest of the Sea_, Simmonds’ _Commercial Products of the Sea_, the publications of the Fisheries Exhibition, especially vol. xi. (Anson and Willett); see also Philpots, _Oysters and all about them_.

[218] Juvenal, _Sat._ iv. 140–142.

[219] _Hist. Nat._ ix. 79.

[220] _Vol. Max._ ix. 1.

[221] _Quart. Journ. Micr. Sc._ xxvi. p. 71.

[222] See G. H. Lewes, _Sea-side Studies_, p. 339.

[223] _Bull. U.S. Fish. Comm._ v. p. 161.

[224] W. Anderson Smith, _Loch Creran_, p. 228.

[225] _Longmans’ Magazine_, June 1889.

[226] _St. James’s Gazette_, 6th January 1893.

[227] Also at Arcachon (W. A. Herdman, _Nature_, 1893, p. 269).

[228] See especially Hoek, _Tijdschr. Ned. Dierk. Vereen_, Suppl. Deel, i. 1883.

[229] _Benderloch_, p. 136.

[230] This is the view of E. Ray Lankester, _Quart. Journ. Micr. Sc._ xxvi. 80.

[231] De Quatrefages, _Rambles of a Naturalist_.

[232] Quoted by Jeffreys, _Brit. Conch._, ii. p. 109.

[233] M. S. Lovell, _Edible Mollusks_, p. 49.

[234] _Science_, vii. p. 175.

[235] _Hist. Nat._ ix. 82.

[236] _De re rustica_, iii. 14.

[237] _Epistles_, i. 15.

[238] Hor. _Sat._ II., iv. 58, tr. Conington.

[239] Roberts, _Zoologist_, 1885, p. 425.

[240] _Hist. Nat._ xxx. 15, 19.

[241] _Science Gossip_, 1891, p. 166.

[242] Jeffreys, _Brit. Conch._ iii. p. 355.

[243] W. Clark, _Mag. Nat. Hist._ xvi. p. 466.

[244] Examples will be found in _Journ. Linn. Soc. Zool._ xi. p. 90; _Ann. Sc. Nat._ xx. p. 472; _Zeit. wiss. Zool._ xxiv. p. 419.

[245] Herdman, _Proc. Liverp. Biol. Soc._ iii. p. 30.

[246] Garrett, _Journ. Ac. Nat. Sc. Phil._ viii. (1880).

[247] J. Bladon, _Zoologist_, xvi. p. 6272.

[248] Lo Bianco, _MT. Zool. Stat. Neap._ viii. p. 414.

[249] _Animal Life_, pp. 126, 135.

[250] R. Rimmer, _Land and Fresh-Water Shells_, p. 119.

[251] _Journ. de Conch._ ii. p. 245.

[252] _Journ. de Conchyl._ iii. p. 107.

[253] Jeffreys, _Brit. Conch._ iii. p. 359; Sauvage, _Journ. de Conchyl._ xxi. p. 122.

[254] Hermaphroditism seems to occur in (_a_) whole families, _e.g._ _Anatinidae_ and the _Septibranchia_; (_b_) genera, _e.g._ _Cyclas_, _Pisidium_; (_c_) single species, _e.g._ in the generally dioecious genera _Ostrea_, _Pecten_, _Cardium_.

[255] δὐω, two; μόνος, single; γόνος, semen; πόρος, passage.

[256] Von Brunn, _Arch. Mikr. Anat._ xxiii. p. 413.

[257] _Hist. Anim._ v. 6 and 12, iv. 1, ed. Bekker, 1837.

[258] ‘On pourra constater si ce ne seraient pas des parties détachées de quelque céphalopode dans le but de servir à le fécondation,’ _Hist. Nat. Helminthes_, 1845, p. 482.

[259] Steenstrup, _Ann. Mag. Nat. Hist._ (2), xx. p. 81 f.

[260] C. Ashford, _Journ. of Conch._ iii. p. 239, iv. pp. 69, 108.

[261] W. E. Collinge, _Zoologist_, 1890, p. 276.

[262] Pelseneer, _Comptes Rendus_, cx. p. 1081.

[263] _Kon. Vet. Akad. Handl._ 1848, pp. 329–435.

[264] _P. Z. S._ 1891, p. 52 f.

[265] The result of some experiments by Professor Herdman upon _Littorina rudis_, tends to show that it can live much better in air than in water, and goes far to support the view that the species may be undergoing, as we know many species must have undergone (see p. 20), a transition from a marine to a terrestrial life. It was found that marked specimens upon the rocks did not move their position for thirty-one successive days (_Proc. Liverp. Biol. Soc._ iv. 1890, p. 50).

[266] Diminutive of κτείς, a comb.

[267] Stoliezka, quoted in _Journ. de Conch._ xviii. p. 452.

[268] ζύγος, a yoke, from the symmetrical position of the branchiae.

[269] Pelseneer, _‘Challenger’ Reports_, vol. xxiii. part lxvi.

[270] _Zoologist_, xii. p. 4248.

[271] _Mollusques de France_, i. p. 81.

[272] _N. Denk. Schw. Ges._ xxix. (2) p. 196 f.

[273] Bergh, _Morph. Jahrb._ x. p. 172.

[274] P. Fischer, _Journ. de Conch._ ix. p. 101.

[275] _Bull. Mus. C. Z. Harv._ xviii. p. 434.

[276] Pelseneer, _Comptes Rendus_, cvi. p. 1029.

[277] _E.g._ Kollmann, _Zeit. wiss. Zool._ xxvi. p. 87.

[278] _Proc. Roy. Soc._ 1873, p. 70.

[279] Griesbach (_Arch. mikr. Anat._ xxxvii. p. 22) finds haemoglobin in several bivalves, _e.g._ _Poromya granulata_, _Tellinata planata_, _Arca Noae_, and _Pectunculus glycimeris_.

[280] _Trans. Roy. Soc. N. S. Wales_, xxii. p. 106.

[281] Pelseneer, _Comptes Rendus_, cx. p. 154.

[282] _Science_, iv. p. 50.

[283] P. Fischer, _Journ. de Conchyl._ (3) xxvii. p. 201.

[284] _Journ. of Conch._ vi. p. 349 ff.

[285] _Quart. Journ. Micr. Sc._ N.S. xv. p. 37.

[286] _Ann. Mag. Nat. Hist._ (2), xx. p. 336.

[287] V. Willem (_Arch. Biol._ ut infr.) denies this, and declares that _Cyclostoma_ is only very sensitive to movements. The present writer has often approached, with the greatest care, a crawling _Cyclostoma_, but it always withdrew into its shell or fell to the ground when approached within about 10 or 12 inches.

[288] _Arch. Biol._ xii. 1892, p. 57.

[289] _‘Challenger’ Reports_, Zoology, vol. xxvii. part lxxiv. p. 3.

[290] _Animal Life_, p. 372 f.

[291] Bergh, _Morph. Jahrb._ x. p. 172.

[292] _Ann. Mag. Nat. Hist._ (5) xiv. p. 141.

[293] The nature of the grouping of the eyes into rows varies considerably in different species. As a rule, the rows radiate from the beak, but occasionally they run parallel to the girdle. In _Tonicia lineolata_ Fremb., they are grouped, as it were, under the shelter of strongly marked longitudinal wavy lines.

[294] =Shell-Eyes in other Mollusca.=--The Rev. J. E. Tenison-Woods (_Trans. Linn. Soc. N. S. Wales_, xxii. p. 106) is of opinion that ‘shell-eyes’ are by no means confined to the Chitonidae, but that, in fact, multiplicity of eyes of this kind is the rule rather than the exception among the Mollusca. He finds (1) exceedingly minute and numerous ‘eyes’ on the outer surface of the shell in both univalves and bivalves; (2) large and solitary ‘eyes’ in the shell substance; (3) eyes on the mantle lobes in both univalves and bivalves; (4) eyes on the opercula.

[295] _Mitth. Stat. Zool. Neap._ v. p. 447 ff.

[296] W. Patten, _Mitth. Zool. Stat. Neap._ vi. (1886) pp. 546, 605 f.

[297] _Benderloch_, p. 136.

[298] _Quart. Journ. Micr. Soc._ xx. p. 443.

[299] _Quart. Journ. of Conch._ i. p. 368.

[300] _British Conchology_, i. p. xxviii.

[301] _Science Gossip_, 1865, p. 259.

[302] _Mollusques de France_, i. p. 130.

[303] _E.g._ Sochaczewer, _Zeits. wiss. Zool._ xxxv. p. 30.

[304] _Zool. Anz._ 1882, p. 472.

[305] _Zoologist_, iv. p. 1266.

[306] _Journ. Mar. Biol. Ass._ N.S. i. p. 217.

[307] Moquin-Tandon, _Moll. de France_, i. p. 133.

[308] _Zool. Jahrb. Anat._ iv. (1890) p. 501.

[309] Baudon, _Rév. Mag. Zool._ 1852, p. 575.

[310] _Arch. Zool. Exp. Gén._ (2) v. 1887, p. 2; compare also C. H. Hurst, _Natural Science_, ii. pp. 360, 421.

[311] Compare Pelseneer, _Bull. Sci. Fr. Belg._ (3) xix. pp. 107, 182.

[312] Pelseneer, _Arch. Biol._ viii. p. 723.

[313] Also known as _labial_ and _supra-oesophageal_ ganglia.

[314] Wivén, however (_K. Sv. Vet. Ak. Handl._ xxiv. 1892, No. 12), describes transverse connectives in _Chaetoderma_.

[315] στρεπτός, twisted; εὐθύς, straight.

[316] With the exception of _Actaeon_, which is streptoneurous (Bouvier, _Comptes Rendus_, cxvi. p. 68).

[317] This fusion of the cerebral and pleural ganglia and the consequent union of the cerebro-pedal and pleuro-pedal commissures can be recognised by sections of the mass (Pelseneer, _Comptes Rendus_, cxi. p. 245).

[318] There is practically no pharynx in the Pelecypoda, the mouth opening directly into the oesophagus.

[319] _Radere_, to scrape; ὸδούς, tooth; φέρειν, to carry.

[320] The mechanism of the radula has been dealt with by Geddes, _Trans. Zool. Soc._ x. p. 485. Rücker has observed (_Ber. Oberhess. Gesell. Nat. Heilk._ xxii. p. 207) that the radula in _Helix pomatia_ is the product of five rows of cells; the use of the first row is uncertain, the second forms the membrane of the radula, while rows three to five originate the teeth.

[321] _Jahrb. Deut. Malak. Gesell._ iii. p. 193.

[322] The whole of the radulae and jaws figured in this work are taken from the original specimens in the collection of the Rev. Prof. H. M. Gwatkin, who has always been ready to give me the run of his cabinets, which probably contain the finest series of radulae in the world. To his kindness I owe the following description of the process of mounting: “The first step is to obtain the radula. Dissection is easy in species of a reasonable size. On opening the head from above, so as to lay open the floor of the mouth, the radula itself is seen in most of the marine species, though in others it is contained in a sort of proboscis; and in the Pulmonata and others the student will find the buccal mass, with commonly a brown mandible at its front end, and the lingual ribbon in its hinder part. The teeth may be recognised by their silvery whiteness, except in a few cases like _Patella_ and _Chiton_, where they are of a deep brown colour. When obtained, the radula may be cleaned by boiling in a solution of caustic potash. There is no risk of injury if the solution is not too strong.

“Smaller species may be treated more summarily. The proboscis, the buccal mass, or even the whole animal may be thrown into the potash solution and boiled till scarcely anything is left but the cleaned radula. Remains of animals dried inside the shell may be similarly dealt with, after soaking in clean water. With a little care, this process will answer for shells down to the size of _Ancylus_ or _Rissoa_. The very smallest (_Carychium_, _Tornatellina_, _Skenea_, etc.) must be crushed on the slide and boiled on it, after removing as much as possible of the broken shell. The radula can then be searched for under the microscope, and washed and mounted on the slide.

“The student must be warned that though the general process is simple, there are difficulties in particular cases. In the Pulmonata, for example, membranes on both sides of the radula need careful removal. _Murex_, _Purpura_, and most of the _Taenioglossa_ have the side teeth folded down over the central, so that the arrangement is not well seen till they have been brushed back. The Cones, again, have no basal membrane at all, so that if the potash is not used with great care, the single teeth will fall asunder and be lost. Perhaps the worst case is where a large animal has a radula as small as that of a _Rissoa_, like _Turritella_, _Harpa_, or _Struthiolaria_, or where the radula is almost filmy in its transparency, like those of _Actaeon_ and the small _Scalaria_.

“When once the radula is laid out, the mounting is commonly easy. Canada balsam makes it too transparent. Fluids may be used, and are almost necessary for thick radulae like those of large _Chitons_; but the best general medium is glycerine jelly. It runs under the cover glass by capillary attraction, and may be boiled (though only for a moment) to get rid of air bubbles. It should then be left unfinished for several weeks. If cracks appear, the reason is either that the jelly is a bad sample, or that it has been boiled too long, or (commonly) that the object is too thick; and there is not often any difficulty in remounting. I have no serious complaint of want of permanence against the medium, if I may speak from a pretty wide experience during the last twenty years.”

[323] The substance both of the jaw and radula is neither crystalline nor cellular, but laminated. Chitin is the substance which forms the ligament in bivalves, the ‘pen’ in certain Cephalopoda, and the operculum in many univalves. Neither silica nor keratine enter into the composition of the radula.

[324] τόξον, arrow; ῥάχις, ridge, sharp edge; ταινία, ribbon; πτηνός, winged; γυμνὀς, bare; ῥιπίς, fan; δοκός, beam.

[325] _V. concinna_, according to Schacko (_Conch. Mitth._ i. p. 126, Pl. xxiv. f. 5); the lateral is large, strong, unicuspid on a broad base.

[326] In some cases (_e.g._ _Hyalinia inornata_) the laterals are very few, while in _Zonites laevigatus_ the first side tooth is more of a marginal than a lateral.

[327] Semon, _Biol. Centralbl._ ix. p. 80.

[328] According to Moquin-Tandon (_Moll. de France_, i. p. 44) this process in _Bithynia_ is attached by one end to the wall of the stomach. _Vivipara_, with two jaw pieces, does not possess this stylet; _Bithynia_, which does possess it, has no jaw.

[329] J. H. Vanstone, _Journ. Linn. Soc._ xxiv. p. 369.

[330] _Biol. Centralbl._ vii. p. 683; _SB. Ges. Nat. Fr._ 1890, p. 42; _Mag. Nat. Hist._ (2) v. 1850, p. 14.

[331] νεφρός, kidney.

[332] _Ann. Mag. Nat. Hist._ (2) xvi. p. 298.

[333] See, for instance, _Quart. Journ. Conch._ i. p. 340 (_Cyl. Raveni_): _Jahrb. Deut. Malak. Gesell._ 1879, p. 98 (_Clausilia dubia_).

[334] Cailliaud, _Journ. de Conchyl._ vii. p. 231; Gassies, _ibid._ p. 44.

[335] _Arch. Naturgesch._ xlii. p. 209.

[336] Dr. W. B. Carpenter, _Rep. Brit. Ass._ xiii. p. 71; xiv. p. 1; xvii. p. 93; J. S. Bowerbank, _Trans. Micr. Soc._ i. p. 123; Ehrenbaum, _Zeit. wiss. Zool._ xli. p. 1.

[337] See also p. 258.

[338] J. E. Gray, _Phil. Trans._ 1833, p. 774 f.

[339] J. E. Gray, _Phil. Trans._ 1833, p. 774 f.

[340] _Journ. de Conchyl._ iv. p. 424.

[341] _Journ. de Conchyl._ xii. p. 3.

[342] T. Scott, _Journ. of Conch._, 1887, p. 230.

[343] M. de Villepoix, _Comptes Rendus_, cxiii. p. 317.

[344] _Proc. Ac. Nat. Sc. Phil._, 1892, p. 350.

[345] Mr. B. B. Woodward has recently pointed out (P. Z. S. 1892, p. 528) a very remarkable method of shell absorption and growth in _Velates_ and certain other Neritidae.

[346] The only exception appears to be _Pedipes_, while in _Cassidula_ and _Scarabus_ the absorption is partial (Crosse and Fischer, _Journ. de Conch._ xxx. p. 177 f.).

[347] _Strombus_ and _Pteroceras_ (see Fig. 99, p. 200) exceptionally develop a siphonal notch which is distinct from the anterior canal.

[348] The _columella_, as distinct from the _columella lip_, is the solid pillar of shell round which the whorls are coiled (Fig. 177), the lower, or anterior portion of which alone is usually visible.

[349] J. E. Gray, _Phil. Trans._ 1833, p. 812.

[350] W. H. Dall, _Amer. Journ. Sc._ xxxviii. p. 445 f.

[351] The term _epidermis_, as distinct from _periostracum_, is properly restricted to the outer layer of the skin of the _mantle_ and body generally.

[352] J. Lewis, _Proc. Bost. Soc._ vi. p. 149.

[353] _Journ. of Conch._ v. p. 66.

[354] _The Dispersal of Shells_, pp. 182–195.

[355] E. A. Smith, _P. Z. S._ 1892, p. 259.

[356] C. T. Musson, _Proc. Linn. Soc. N. S. Wales_ (2), v. p. 883.

[357] _Scient. Results Sec. Yarkand Exped._ “Mollusca,” pp. 1–16.

[358] Mr. H. W. Kew, _The Dispersal of Shells_, has brought together a very large series.

[359] _The Naturalist in Nicaragua_, p. 334 f.

[360] Morelet, _Journal de Conch._ 1875, p. 194.

[361] Pollonera, _Boll. Mus. Zool. Torino_, v. 1890, No. 87.

[362] South and south-western France, however, belong to the Mediterranean Sub-region.

[363] The coast-line of north-east China, including Corea and Japan to north Niphon, is much more definitely tropical than the adjacent inland districts. The coast-line, therefore, must be placed in the Oriental Region, while the inland districts belong to the Palaearctic Region.

[364] _Biol. Centralbl._ ii. p. 208.

[365] Craven, _Journ. de Conchyl._ (3) xxviii. p. 101.

[366] _Jahrb. Deutsch. Malak. Gesell._ viii. p. 278.

[367] Netchayeff, _Kazan Soc. Nat._ xvii. fasc. 5.

[368] _Fauna der Congerien-Schichten_, p. 142.

[369] _Streptaxis_ is a remarkable instance of a _mainland_ genus. Although abundant in the Oriental, Ethiopian, and Neotropical regions, it never seems to occur on any of the adjacent islands, except in the case of Trinidad (1 sp.), which is practically mainland. _Omphalotropis_, on the other hand, is the exact reverse of _Streptaxis_ in this respect, occurring all over Polynesia and the Malay Is., as far west as Borneo, as well as on the Mascarenes, but never, save in a doubtful case from China, on the mainland of Asia, Australia, or Africa.

[370] The Amboyna group has been much the better explored. Common to both groups are one sp. each of _Kaliella_, _Trochomorpha_, _Opeas_, _Leptopoma_, _Cyclotus_, _Helicina_.

[371] A. H. Cooke, _P. Z. S._ 1892, pp. 447–469.

[372] Mysol, with 2 _Chloritis_, 1 _Insularia_, 1 _Cristigibba_, is decidedly Papuan.

[373] See especially C. Hedley, Note on the Relation of the Land Mollusca of Tasmania and New Zealand, _Ann. Mag. Nat. Hist._ (6) xiii. p. 442.

[374] Hedley and Suter, _Proc. Linn. Soc. N. S. Wales_ (2), vii. p. 613. Twenty-one species are “introduced.”

[375] Nine species have been introduced: 6 from Europe, 2 from the West Indies, 1 from the Western Isles.

[376] It is by no means implied that _unbroken_ land communication between India and Madagascar, across the Indian Ocean, ever existed. A series of great islands, whose remains are attested by the Chagos and other banks, would be quite sufficient to account for the results, as we find them. See especially Medlicott and Blanford, _Geology of India_, vol. i. p. lxviii.

[377] _Journ. Cinc. Soc. Nat. Hist._ iii. p. 317. The number is doubtless susceptible of very considerable reduction, say by one-half at least.

[378] Simpson, _Amer. Nat._ xxvii. 1893, p. 354.

[379] Compare von Martens, _Malak. Blätt._ 1868, p. 169; von Ihering, _Nachr. Deutsch. Malak. Gesell._ 1891, p. 93.

[380] The distribution of some Pteropoda has been worked out by Munthe, _Bih. Svensk. Ak. Handl._ XII. iv. 2, by Pelseneer _“Challenger” Rep._, Zool. xxiii., and by Boas, _Spolia Atlantica_.

[381] _Bull. Mus. C. Z. Harv._ xiv. p. 202; xxiii. p. 34 f.

[382] See papers in _P. Z. S._ 1878–85.

[383] A break in this uniformity may be found underneath the course of a great oceanic current like the Gulf Stream, which rains upon the bottom a large amount of food. A. Agassiz (_Bull. Mus. C. Z. Harv._ xxi. p. 185 f.) explains in this way the richness of the fauna of the Gulf of Mexico as compared with that of the west coast of tropical America.

[384] On the western coasts of Europe and America, where the change in surface temperature is very gradual, _Purpura lapillus_ (the west American ‘species’ are at best only derivatives) is able to creep as far south as lat. 32° (Mogador) in the former case, and lat. 24° (Margarita Bay) in the latter, the mean annual temperature of the surface water being 66° off Mogador, with an extreme range of only 8°, and that of Margarita Bay 73°, with an extreme range of only 5°. On the eastern coasts, where the Pacific and Atlantic gulf-streams cause a sudden change of temperature, the _Purpura_ is barred back at points many degrees farther north, _viz._ at lat. 41° (Hakodadi), surface temperature 52°, extreme range 25°; and at lat. 42° (Newhaven), surface temperature 52°, extreme range 30°.

[385] E. A. Smith, _P. Z. S._ 1890, pp. 247, 317.

[386] A. H. Cook, _Ann. Mag. Nat. Hist._ (5) xviii. (1886) p. 380 f; E. A. Smith, _P. Z. S._ 1891, p. 391 f.

[387] C. Keller, _Neue denksch. Schw. Gesell._ xxviii. 1883, pt. 3.

[388] According to Tate (_Trans. Roy. Soc. S. Austr._ 1887–88, p. 70), ‘Australian’ species predominate at Freemantle (32°), but Tenison-Woods (_J. Roy. Soc. N. S. Wales_, xxii. p. 106) holds that the tropical fauna extends as far south as Cape Leeuwin (34°), and that the Australian forms are not predominant until the extreme south. Tenison-Woods regards Cape Byron (31°) as the limit of the tropical fauna on the east coast, while some characteristic tropical genera reach Port Jackson, and a few (_e.g._ _Cypraea annulus_) Tasmania.

[389] A full account of the distribution of _Voluta_ is given by Crosse, _Journ. de Conchyl._ (3) xix. p. 263.

[390] Usually known as ‘Patagonian,’ but since the Magellanic Sub-region includes a considerable part of Patagonia, and since the greater part of sub-region (6) lies out of Patagonia, it has been thought advisable to change the name.

[391] _Amer. Nat._ xx. p. 931.

[392] W. H. Dall, _Proc. Biol. Soc. Washington_, v. p. 1 f.

[393] _Trans. Connect. Acad._ v. p. 177; _Zoologist_, 1875, p. 4502.

[394] _Rep. Scotch Fish._ iii. 1885, App. F, p. 67.

[395] _Nautilus_, vi. 1892, p. 82.

[396] _Journ. Mar. Zool._ i. pp. 3, 9.

[397] _Rep. Brit. Assoc._ 1844, Transactions, p. 74; _P. Z. S._ 1839, p. 35.

[398] It is convenient, but not morphologically correct, to apply the terms ‘ventral’ and ‘dorsal’ in this sense.

[399] φραγμός, partition; σήπιον, cuttle-bone; χόνδρος, long cartilage.

[400] μυέω, close the eyes; ὕψις, sight; contrasted with Oigopsidae (οἰγω, open).

[401] The classification is that of Foord, _Catal. Fossil Cephal. Brit. Mus._, 1888.

[402] Saville Kent, _Proc. Roy. Soc. Queensland_, vi. p. 229.

[403] J. Power, _Ann. Mag. N. H_. (2) xx. p. 334; _P. Z. S._ 1836, p. 113; _Arch. Zool. Exp. Gén._ (3) i. 1893, p. 105.

[404] In deference to Bergh’s high authority, the position of a sub-order is here given to the Ascoglossa. It may be doubted whether that position will stand the test of further investigation, and whether the families concerned will not be added to the Cladohepatic Nudibranchs.

[405] This family has also been classified with the Bulloidea and with the Aplysioidea.

[406] It appears more convenient to treat the whole group together, rather than deal with the two sections separately.

[407] An operculum is said to exist in the young forms of _Auricula_ and _Parmacella_.

[408] _Proc. Ac. Philad._ 1892, p. 390.

[409] Compare Jackson, _Amer. Nat._ xxv. p. 11 f.

[410] “A Monograph of the British Fossil Brachiopoda,” _Palaeontographical Society_, London, vols. i.-v. 1851–84.

[411] _Ibid._ vol. vi. 1886.

[412] “Contributions to the Anatomy of the Brachiopoda,” _Proc. Roy. Soc._, vol. vii.

[413] “Untersuchungen über den anatomischen u. histologischen Bau der Brachiopoda Testicardinia,” _Jenaische Zeitschrift_, vol. xvi., 1883.

[414] “On a living Spinose _Rhynchonella_ from Japan,” _Ann. Mag. Nat. Hist._, 5th ser., vol. xvii., 1886

[415] _Loc. cit._ p. 465.

[416] Shipley, “On the Structure and Development of Argiope,” _Mitt. aus d. Zool. Stat. zu Neap._ Bd. iv. 1883.

[417] Schulgin, “Argiope Kowalevskii,” _Zeit. f. wiss. Zool._ Bd. 41, 1885.

[418] _American Jour. of Sci. and Arts_, 3rd series, vol. xvii. 1879.

[419] _Loc. cit._ p. 470.

[420] “Recherches sur l’Anat. des Brachiopodes Inarticules,” _Arch. Zool. Exp._ (2), Tome iv., 1886.

[421] “Untersuchungen über den Bau der Brachiopoden,” Jena, 1892.

[422] “Vorläufige Mittheilungen über Brachiopoden,” _Zool. Anz._ Bd. viii. 1885.

[423] Hancock’s nomenclature is here used. The corresponding names used by King and Brooks are placed in brackets. Their nomenclature is used by many palaeontologists, and is adopted in Fig. 322.

[424] _Development of the Brachiopoda_, 1873 (Russian).

[425] “Histoire de la Thécidie,” _Ann. d. Sci. Nat._, Sér. 4, vol. xv., 1861.

[426] “On the Early Stages of Terebratulina septentrionalis,” _Mem. Boston Soc. Nat. Hist._, vol. ii., 1869. “On the Development of Terebratulina,” _Ibid._ vol. iii., 1873.

[427] “Choses de Nouméa,” _Arch. d. Zool. exp. et gen._, 2nd ser., vol. ix., 1891.

[428] J. Barrande, _Syst. Silur. Bohème_, vol. v., 1879. Hall and Clarke, _Introd. Palaeozoic. Brach._ (_Palaeont. of New York_, 1892–1894). Davidson, _Monogr._ _Brit. Foss. Brach._ (_Palaeont. Soc._, 1851–1884). Waagen, _Salt Range Fossils_ (_Mem. Geol. Surv. India_, 1879–1885).

[429] The results of the investigations of King (_Ann. Mag. Nat. Hist._, 4th ser., vol. xii., 1873) and of Brooks (_Chesapeake Zool. Laboratory, Scientific Results_, p. 35, 1879), and the simple nomenclature of these authors are here followed in preference to those of others, owing to the difference of opinion amongst anatomists of the functions and homologies of the muscles. The lateral muscles enable the valves to move backwards and forwards on each other; the centrals close the shell; the umbonals open it; and the transmedians allow a sliding sideways movement of one valve across the other (see also p. 477).

[430] Davidson and King, _Quart. Jour. Geol. Soc._, xxx. (1874), p. 124.

[431] _Amer. Jour. Science_, 1890–1893.

Transcriber’s Notes:

1. Obvious printers’, punctuation and spelling errors have been corrected silently.

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