CLASS IV 



GASTROPODA 



553 



Bimella Agassiz {Isopleura Meek) (Fig. 996). Surface cancellated. Outer lip 

 with tliickened inargin, entire or 

 creniüated. Upper Cretaceous to Re- 

 cent. 



Orthaulax Gabb. Spire wholly 

 iiivolute and hidden. Oligocene ; 

 Antilles. 



Family 20. 

 Oolumbellariidae 



Fischer, 



Fig. 996. 



A, liimella fismrella (Lam.). 

 Calcaire Grossier ; Damery, 

 near Epernay. B, lt. hartonensis 

 (Sowb.). Calcaire Grossier; 

 Griguon, near Paris. 



Shell thick, elongated 

 oval, with short conical 

 spire, and large, spirally 

 ribbed, frequently cancel- 

 lated body lohorl. Äper- 

 ture narrow, anteriorly with short canal, and pos- 

 teriorly with a canal directed obliquely outwar ds. 

 Inner lip callous, outer lip often thickened, denti- 

 culated or somewhat reflected outwardly. Jura and 

 Cretaceous. 



HijipoiJiKiif^ iii}ii(hisoni Dc^h. Calcaire 

 Grossier ; Damery, neai Epernay. 



Fi(!. 997. 



^ , ^ „ . , Fig. 998. Fig. 999. 



Columbellaria coral- 



lina (Quenst.). Zittclia crasslsaima Fetersia costata 



Ooral-Rag; Nat- (Zitt.). Tithonian; Gemm. Tithonian ; 



theim. Stramberg. Palermo. 



Columbellaria Rolle (Fig. 997). Surface covered with nuraerous spiral ribs, 

 sometimes cancellated. Aperture long and narrow, broadening somewhat anteriorly. 

 Outer lip denticulated internally, not thickened, somewhat reflected. Anterior and 

 posterior canals short. Upper Jura. 



Zittelia Gemm. (Fig. 998). Like the last, but aperture very narrow or cleft-like. 

 Outer lip much thickened in the middle. Tithonian. 



Golumbellina d'Orb. Cretaceous. Petersia Gemm. (Fig. 999). 

 Tithonian. 



Family 21. Oypraeidae Gray. Cowries. 



Shell ovate, convolute. Spire short, nearly or completely covered. in 

 the adult by the very large body ivhorl. Aperture of equal length ivith 

 the shell, narroio, anteriorly and posteriorly produced in a usually short 

 canal. Outer lip inflected. Operculum wanting. Upper Jura to 

 Recent. 



Recent Cypraeidae of which about 210 species are known, 

 inhabit principally the warmer seas. They are often remarkable for 

 their beautiful coloration, and sometimes attain considerable size. Jurassic species are 

 sparse ; Tertiary ones rather more abundant. 



Cypraea Linn. (Fig. 1000). Ovoid, ventricose, enamelled, smooth, lirate or 



I !iprn,,f Silin, r,s 



A. Jirauii. Uligc 

 cene ; Weinliein 

 near Alzey. 



