314 MANUAL OP THE MOLLUSCA. 



twisted, and directed slightly outwards. (B.) Shell oval, spire 

 sunk, whorls v/ith acute margins. Bath Oolite, Britain. 



Adeonina, D'Orbigny. Tornatelloe '' without columella 

 plaits," 30 species. Garb. — Portlandian (including Cylindrites). 



AdeoneUa, D'Orbigny. A. Eenauxiana, PI. XIY., Fig. 3. 

 Shell thick, cone-like or convoluted, spire short or concealed, 

 apertui-e long and narrow, columella with 3 strong and regular 

 spiral plaits in front. Distribution, 18 species. Chalk ; Britain, 

 France. 



Acteon Cahanetiana, D'Orbigny. [Itieria, Matheron, 1842), 

 Coral-rag, France, belongs to the genus Nerin(£a (D'Orbigny), 

 p. 244. 



CiNULiA, Gray. 



Type, C. avellana, PI. XIV., Fig. 4. 



Synonyms, Avellana and Einginella, D'Orbigny. 



Shell globular, thick, spirally grooved and punctate, spire 

 small ; aperture narrow, rounded and sinuated in front ; outer 

 lip thickened and reflected ; crenulated inside, columella with 

 several tooth-like folds. 



Fossil, 21 species. Neocomian — Chalk. Britain, France. 



EiNGicuLA, V. p. 222, PI. v.. Fig. 21. 

 Globiconcha, D'Orbigny. 

 Type, G. rotundata, D'Orbigny. 

 Fossil, 6 species. Chalk. France. 

 Shell ventricose, smooth, aperture crescent-shaped, simple, 

 not toothed or thickened on the columellar side. 



Varigera, D'Orbigny. 1850.* 



Type, Y. Guerangi, D'Orbigny. 



Fossil, 8 species. Neoc : — . Chalk. France. 



Shell like Globiconcha, but with lateral varices. 



Tylostoma, Sharp. 1849. 



Type, T. Torrubioe, Sharp. 



Etymology, 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 whorl) thickened inside and 

 expanded, rising slightly ; inner lip callous, spread over body- 

 whorl. 



Distribution, 4 species. L. Cretaceous rocks, Portugal. 



* 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 ytdrs 

 afterwai'ds. 



