1 88 THE GASTROPODA 



Scopoli ; shell ovoid, with oval or elongated aperture and a thickened 

 border. Hemphillia, Binney and Bland ; shell unguiform, its edges 

 covered by the mantle ; North America. Kerendtia, Crosse and Fischer. 

 Cochlostyla, Ferussac. Rhodea, Adams. FAMILY 8. ENDODONTIDAE, 

 Pilsbry. Shell spiral, external, generally ornamented with ribs ; borders 

 of the aperture thin and not reflected ; radula with square teeth ; genital 

 ducts without accessory organs. Genera Endodonta, Albers. Punctum, 

 Morse. Sphyradium, Charpentier. Laoma, Gray. Pyramidula, Fitzinger. 

 FAMILY 9. ORTHALICIDAE, Fischer. Shell external, ovoid, the last whorl 

 swollen, the aperture oval, with a simple border ; radular teeth in oblique 

 rows. Genus Orthalicus, Beck ; American. FAMILY 10. BULIMULIDAE. 

 Fischer ; jaw formed of folds imbricated externally and meeting at an 

 acute angle near the base. Genera Bulimulus, Leach ; shell elongated, 

 oval, external. Peltella, Webb and van Beneden ; shell auriform, in- 

 ternal. Amphibulimus, Montfort. FAMILY 1 1. CYLINDRELLIDAE, Fischer. 

 Shell turriculated, with numerous whorls, the last whorl more or less 

 detached. Genus Cylindrella, Pfeiffer ; aperture circular, with reflected 

 peristome ; summit commonly truncated ; America. FAMILY 12. PUPIDAE, 

 Fleming. Shell external, with elongated spire and numerous whorls ; 

 aperture generally narrow ; male genital duct without multifid vesicles. 

 Genera Pupa, Lamarck ; shell cylindrical, dextral with obtuse summit ; 

 aperture parallel to the axis, small and contracted ; British. Eucalodiuni, 

 Crosse and Fischer ; shell turriculated, the summit truncated, the aperture 

 oval. Vertigo, Midler ; shell small, ovoid, the summit obtuse, the aperture 

 small and contracted by numerous teeth ; dextrally or sinistrally coiled ; 

 a single pair of tentacles ; British. Jhdiminus, Ehrenberg ; shell 

 umbilicated, ovoid, with elongated aperture and a simple columella ; 

 British. Clausilia, Draparnaud ; shell turriculated, sinistral ; aperture 

 oval ; the columella with corrugations and a movable piece, the 

 clausilium, by means of which the mouth of the shell can be closed ; 

 British. Balea, Prideaux ; shell sinistral, differs from Clausilia in the 

 absence of columellar corrugations and clausilium. Zvspeum, Bourguignat ; 

 no eyes, shell short and dextral. Megaspira, Lea. Strophia, Albers. 

 Anostoma, Fischer. FAMILY 13. STENOGYRIDAK, Fischer. Shell elongated, 

 with a more or less obtuse summit ; aperture oval with a simple border. 

 Genera Achatina, Lamarck ; shell ovoid, the spire conical, the last 

 whorl ventricose ; the columella twisted. Stmoyyra, Shuttleworth ; shell 

 turriculated ; the whorls numerous, increasing slowly (Fig. 8). Fcrussacia, 

 Risso ; shell small, thin, and brilliant ; aperture elongate, oval ; British. 

 Caecilianella, Ferussac ; shell cylindrical, the spire elongated, the columella 

 truncated ; eyes absent ; subterranean in habit ; British. Cianclla, 

 Jeffreys. Azeca, Leach. Opeas, Albers. RJuxlea, Adams. FAMILY 14. 

 HELICTERIDAE, Fischer. Shell bulimoid, dextral or sinistral ; radular teeth 

 narrow at their bases, expanded at their extremities and multicuspidate. 

 Genera Helicter, Ferussac. Tornatellina, Beck. 



TRIBE 2. AGNATHA. 



No jaws ; the radular teeth narrow and pointed ; carnivorous. This 

 group is possibly polyphyletic. 



