814 MANUAL OF THE MOLLITSCA. 



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

 Bunk, whorls with acute margins. Bath Oolite, Britain. 



Adeonina, D'Orbigny. Tornatellse "without columella 

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



Adeonella, 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. 



Adeon Cahanetiana, D'Orbigny. {Itieria, Matheron, 1842), 

 Coral-rag, France, belongs to the genus NeriiKxa (D'Orbigny), 

 p. 244. 



CiNULlA, Grray. 



Type, C. avellana, PL XIY., Fig. 4. 



Sy7io)iyms, Avellana and Einginella, D'Orbigny. 



Shell globular, thick, spii'ally 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, Q-. rotundata, D'Orbigny. 

 Fossil, 6 species. Chalk. France. 



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

 not toothed or thickened on the columellar side. 



Yaeigera, D'Orbigny. 1850.* 



Type, Y. Guerangi, D'Orbigny. 



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



Shell like GlohiconcJia, but with lateral varices. 



Tylostoma, Sharp. 1849. 



Type, T. Torrubise, 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 Paleontologtt, dXQ 

 dates of invention ; the names were not published, in many instances, until y€/\i'8 

 ^terwardji, 



