GASTEROPODA. 181 



narrow, rounded and sinuated in front ; outer lip thickened and reflected ; 

 crenulated inside, columella with several tooth-like folds. 

 Fossil, 20 sp. Neocomian Chalk. Brit. France. 



RINGICTJLA, v. p. 112, PI, V. fig. 21. 



GLOBICONCHA, D'Orbigny. 



Type, G. rotundata, D'Orb. Fossil, 6 sp. Chalk. France. 

 Shell ventricose, smooth, aperture crescent-shaped, simple, not toothed 

 or thickened on the columellar side. 



VARIGERA, D'Orbigny. 1850.* 



Type, V. Guerangeri, D'Orb. Fossil, 8 sp. Neoc: . Chalk. France. 

 Shell like Gloliconcha, but with lateral varices. 



TYLOSTOMA, Sharp. 1849. 



Type, T. Torrubiee, Sh. Etym. Tulos, a callosity, stoma, mouth. 



Shell ventricose, smooth or punctate-striate, spire moderate, aperture 

 ovate-lunate, pointed above, rounded in front ; outer lip periodically (once or 

 twice in a whirl) thickened inside and expanded, rising slightly ; inner lip 

 callous, spread over body- whirl. 



Distr. 4 sp. L. Cretaceous rocks, Portugal. 



? PTERODONTA, D'Orbigny. 



Type, P. inflata, D'Orb. Fossil, 8 sp. Chalk. France. 



Shell oblong, ventricose, spire elongated ; aperture oval, lip slightly ex- 

 panded, notched in front, and with a tooth-like ridge internally, remote from 

 the margin. 



? TORNATINA, A. Adams. 



Type, T. voluta. PL XIV. fig. 5. 



Shell cylindrical or fusiform, spire conspicuous, apex sinistral, suture 

 channelled, columella callous, 1- plaited. 



Animal with a broad, trigonal head, rounded in front ; tentacular lobes 

 triangular, with eyes at their outer bases ; foot short, truncated in front. 



Distr. 15 sp. W. Indies, TL States, Medit. Philippines, China, Australia. 

 On sandy bottoms, ranging to 35 fms. (Adams). 



Volvula, Adams (Bulla acuminata, Brug.) is a small convoluted shell, with 

 the spire concealed, and the columella obsoletely folded; it is referred to 

 Cylichna by Loven, to Ovulum by Forbes. Distr. Brit. Medit. Fossil. 

 Miocene . Suffolk. 



FAMILY II. BULLION. 



Shell globular or cylindrical, convoluted, thin, often punctate-striated ; 



* The dates of M. D'Orbigny's genera, given in the Prodrome de Paleontologie. 

 are dates of invention ; the names were not published, in many instances, until years 

 afterwards. 



