302 PHASIANELLID^, 



somewhat embracing above, and each hiding all the preceding 

 ones below ; aperture wider than high ; peristome not continuous ; 

 labrum simple, projecting forward above; labium a little sinuous 

 and slightly spreading in the more or less impressed umbilical 

 region. 



PiTONELLUS, Montfort. 



Sy7i. — Ptychomphalus, Agassiz. Lewisiella, Stolicz. 



Distr. — Lias, Cretaceous ; Europe. P. archiaeianus, d'Orb. 

 (Ixxix, 2). P. conicus^ d'Orb. (Ixxix, 3). 



Shell depressed or conic, whorls generally rounded, the base 

 with a very strong shining callus ; lip simple, sharp. 



Crossostoma, Morris and Lycett. 



Distr. — 2 sp. Oolite; England. G. Prattii, Morris and 

 Lycett (Ixxix, 4). 



Shell thick, depressed turbinated, without umbilicus ; aper- 

 ture subrotund, entire ; outer lip smooth ; columella toothed 

 when young, tooth concealed by callus in the adult. 



TROCHOPSis, Gemmellaro, 1878. Shell top-shaped, thick, shining, 

 imperforate ; outer lip with four inferior tuberculate spiral ribs ; 

 inner lip curved, sharply defined by a furrow. C. Moroi, Gemm. 

 Liassic. 



Pterocheilos, Moore. 



Dish: — P/. pWmws (Ixxix, 5). Liassic; England. 



Yery thick, small, with the general contour angulated or 

 rhomboidal, smooth, spire short, periphery of last whorl cari- 

 nated, the carina terminating in a wing-like projection of the 

 outer lip; aperture with a thick, circular peristome, columella 

 thick, folded, subumbilicated, greatly extending beyond the 

 peristome, and possessing a wide but shallow sulcus towards 

 its base. 



Pleuratella, Moore, 1867. 



Distr. — P. prima^ Moore. Lias ; Europe. 



Shell small, thick, smooth ; spire much depressed ; whorls 

 4-5, rapidly enlarging ; last whorl very large, rounded ; aperture 

 round or oval ; inner lip straight, with thick lengthened colu- 

 mella, having an umbilicus-like groove. 



Family PHASIANELLID^. 



Shell bulimiform, smooth, polished, richly ornamented with 

 bright colors, without epidermis. Operculum oval, calcareous. 



Animal with long ciliated tentacles ; head-lobes pectinated, 

 wanting in the minute species ; neck-lobes fringed ; sides orna- 

 mented with three cirri ; branchial plume long, partly free ; foot 

 rounded in front, pointed behind. 



Distinguished from the Tiirbinidae by the form of the shell, 



