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. 



RiNGICULA, V. p. 112, PI. V. fig. 21. 

 Globiconcha, D'Orbigny. 

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

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

 or thickened on the columeUar side. 



Varigeua, D'Orbigny. 1850.* 

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

 Shell like Gloiiconcha, but with lateral varices. 



Tylostoma, Sharp. 1^49. 



Type, T. Torrubise, 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-Hke ridge internally, remot-e from 

 the margin. 



? ToRNATiNA, A. Adams. 



Type, T. voluta. PI. XTV. fig. 5. 



Shell cylindi'ical or fusiform, spire conspicuous, apex sinistral, suture 

 channelled, columella callous, 1-plaited. 



Animal with a broad, trigonal head, rounded in fi'ont ; tentacular lobes 

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



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

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



Volvula, Adams (Bulla acuminata, Brug.) is a small convoluted sheU, -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 — . Suffolli. 



FAMILY II. BuLLiD^. 



S}oell globular or cylindrical, convoluted, thin, often punctate-striated ; 



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

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

 afterwards. 



