514 MOLLUSC A phylum yi 



Class 4. GASTROPODA. SnailsJ 



MoUuslcs ivith distinct head, soled or more rarely Jin-like foot, and undivided 

 mantle, which latter usually secretes a univalve, sjnrally wound, or saucer-shaped shell. 



Gastropods differ from Pelecypods in having a more or less distinctly 

 marked head, which usually bears tentacles, eyes, and ears, and contains a 

 large cerebral ganglion. The ventral aspect of the creature is commonly 

 formed by a broad foot ; but in the Heteropoda this is modified into a vertical, 

 laterally compressed fin ; and in the Pteropoda it is represented by two wing- 

 like swimming membranes near the head. The base of the foot is sometimes 



^ Literature (see also under head of Mollusca, antea) : Ihering, H. v., Vergleiclieiide Anatomie 

 des Nervei) systems iiud Phylogeuie der MoUusken. Leipsic, 1877. — Koken, E., Uber die Eut- 

 wickelung der Gastropoden vom Kambrium bis zur Trias. Neues Jahrb. f. Mineral., 1889, supplem. 

 vol. vi. — Quenstedt, F. A., Petrefaktenkuude Deutsclilands. Gastropoden, vol. vi., 1881. — Simroth, 

 H., Gastropoda, in Broun's Klasseu uud Ordnungen des Tien-eichs, 1896. — Troschel, H., Das 

 Gebiss der Sclmecken, zur Begriindung einer natiirlichen Classification, vols, i., ii. Berlin, 1856-78. 



A. On Paleozoic Forms. — Billings, E., Palaeozoic Fossils. Geol. Surv. Canada, 1865-74, vols, i., 

 ii. — Jakoialeiu, V., Die Fauna eiuiger oberpaliiozoischer Ablagerungen Russlands. Mem. Coniite 

 Geol., 1899, vol. XV., No. 3. — Koken, E., Die Gastropoden des baltischen Untersilurs. Bull. Acad. 

 Imp. Sci. St. Petersb., 1897, vol. vii.. No. 2. — Koninck, L. G. de, Faune du calcaire carbonifere 

 de la Belgique. Ann. Mus. d'Hist. Nat. Belg., 1882-85, vol. vi. — LindstrlJm, G., On the Silurian 

 Gastropoda and Pteropoda of Gotland. K. Svensk. Vetensk. Akad. Handl., 1884, vol. xix. 

 — Perner, J., Gasteropodes, in Barrande's Systeme silurien du centre de la BohOme, vol. iv. 

 Prague, 1903-7. — Salter, J. W., Catalogue of the collection of Cambrian and Silurian fossils in 

 the Museum of Cambridge, 1873. — Spitz, A., Die Gastropoden des karnischen Unterdevon. Beitriige 

 Pal. nnd Geol. Osterr.-Ung., etc., 1907, vol. xx. — Ulrich, E. 0., and Scqfield, W., The Lower 

 Silurian Gastropods of Minnesota. Rept. Geol. and Nat. Hist. Surv. Minn., 1897, vol. iii., pt. 2. 



B. On Mesozoic Forms. — Ahlbiirg, J., Die Trias im s. Oberschlesien. Abhandl. Preuss. Geol. 

 Landesanst. n. Bergakad., 1906, n.s.. Heft 50. — Bijhm, J., Die Gastropoden des Marmolatakalkes. 

 Paliiontogr., 1895, vol. xlii. — Brosamlen, R., Beitrag zur Kenutuis der Gastropoden des schwiibischen 

 Jura. Paliiontogr., 1909, vol. Ivi. — De^iingei; K., Die Gastropoden der siichsischen Kreideformation. 

 Beitrage Pal. und Geol. Osterr.-Ung., etc., 1905, vol. xviii. — Haberle', D., Paliiontologische Unter- 

 suchungen triadischer Gastropoden ans dem Gebiet von Predazzo. Verhandl. Naturh. Med. Vereins. 

 Heidelberg, 1 908, n.s., vol. ix. — Iludlcston. W. //., A Monograph of the British Jurassic Gasteropoda. 

 Paliiontogr. Soc, 1887-94. — Kanjilinven, F., Die Gastropoden der Mitstricher Kreide. Paliiont. 

 Abhandl., 1897, n.s., vol. iv. (viii.). — Koken, E., Die Gastropoden der Trias um Hallstadt. Jalirb. 

 Geol. Reichs-Anst. Wien, 1897, vol. xlvi., and Abhandl., vol. xvii. — Morris, J., and Lycett, J., 

 Mollusca from the Great Oolite : Univalves. Palaeontogr. Soc, 1850. — d'Orbigny, A., Paleontologie 

 fran(;aise. Terrains jurassiques ii. et iii., 1850-82. Terrains cretaces ii., 1842-3. — Picard, E., 

 Beitrag zur Keuntnis der Glossophoren der mitteldeutschen Trias. Jahrb. Preuss. Landesanst., 

 1901, vol. xxv. — Stolii'zka, F., Cretaceous Fauna of Southern India. Gastropoda, vol. ii. Mem. 

 Geol. Surv. East India, 1808. — Zittel, K. A., Die Gastropoden der Stramherger Schichten. Mitt. 

 Mus. Bayer. Staates, 1873, vol. ii., pt. iii. 



C. On Tertiary Forms. — Beyrich, E., Die Couch ylien des norddeutschen Tertiiirgebirges. 

 Zeitschr. Deutsch. Geol. Ges., 1853-6, vols, v., vi., viii. — Cossmann, M., MoUusqiies eoceniqnes 

 de la Loire-Inferieure, i. and ii. Bull. Soc. Sci. Nat. Quest Nantes, vols, vii.-ix., 1895-1901. 

 Contribiition .a la paleontologie franeaise des terrains jurassiques. Mem. Soc. Geol. France, 1895, 

 1898, Mem. Nos. 14 and 19. Essais de pah'outologie comparee, i.-iv. Paris, 1895-1904. — Cossmann, 

 M., and Pissarro, G., Faune eocenique du Cotentin. Bull. Soc. Geol. Normandie, 1900-2, vols, xix.- 

 xxi. — Dall, W. H., Contributions to the Tertiary Fauna of Florida. Trans. Wagner Free Inst. Sci., 

 1895-97, vols, iii., v. — Harris, G. F., The Australasian Tertiary Mollusca. Cat. Tert. Mollusca 

 Brit. Mus., pt. i., 1897. — Hoernes, R., and Aninger, M., Die Gastropoden der Meeresablagerungen 

 der ersteu und zweiten Mediterranstufe. Vienna, 1879-91. — Martin, K., Die Fossilien von Java. 

 Samml. Geol. lleichsmus. Leiden, 1895-99, n.s., vol. i., pts. 2-10. — Newton, R. B., Systematic List 

 of British Oligocene and Eocene Mollusca, 1891. — Philipj^i, R. A., Die tertiiiren und quartiiiren 

 Versteineruugen Chiles. Leipsic, 1887. — Sandberger, F., Land- und Siisswasserconchylien der 

 Vorvvelt. Wiesbaden, 1870. — Vinassa de Regny, P. E., Synopsis dei molluschi terziari delle Alpe 

 venete. Palaeontogr. Italica, 1896-97, vols, i., ii. — Wood, E., Tlie Phylogeny of certain Cerithiidae. 

 Ann. N.Y. Acad. Sci., 1910, vol. xx. — Grufiaii, A. W., Studies of Gastropoda. Amer. N.at., 

 1902-3, vols, xxxvi., xxxvii. — Phylogeny of Fusus. Smiths. Misc. Coll., 1904. 



