472 



MOLLUSCA 



SUB-KINGDOM VI 



dilated anteriorly ; canal short. Outer margin thin, simple, obliquely truncated 



anteriorly, sometimes prolonged in 



the spire posteriorly by a callosity. 



Columellar border smooth, straight. 



Tertiary and Recent. 



Rostellaria, Lam. Spire high, 



whorls smooth. Aperture produced 



anteriorly in a beak-like canal, and 



continued posteriorly as a narrow 

 channel resting on the 

 spire. Outer margin 

 with denticulate pro- 

 cesses, notched anteriorly. 



Late Tertiary and 4, Rimella fissurella, Lam. 

 -p Calcaire Grassier ; Damery, 



- n t. near Epernay. B, R L Barton - 



Hippochrenes, Montf. 

 (Orthauiax, Cyclolomops, 



Gabb), (Fig. 946). Like the last, but outer 

 margin expanded in wing - like fashion, and 

 destitute of processes. Upper Cretaceous and 

 Eocene. 



Rimella, Agassiz (Isopleura, Meek), (Fig. 947). 

 Surface cancellated. Outer lip with thickened 

 margin, entire or crenulated. Upper Cretaceous 

 to Recent. 



Family 20. Columbellariidae. Fischer. 



Shell thick, elongated oval, with short conical 

 spire, and large, spirally ribbed, frequently can- 

 cellated body whorl. Aperture narrow, anteriorly 

 with short canal, and posteriorly with a canal 

 directed obliquely outwards. Inner Up callous, 



outer lip often thickened, denticulated, or somewhat reflected outwardly. Jura and 



Cretaceous. 



Oolumbellaria, Rolle (Fig. 948). Surface covered with numerous spiral ribs, some- 

 times cancellated. Aper- 

 ture long and narrow, 

 broadening somewhat 

 anteriorly. Outer lip 

 denticulated internally, 

 not thickened, somewhat 

 reflected. Anterior and pos- 

 terior canals short. Upper 

 Jura. 



Zittelia, Gemm. (Fig. 

 9 4 9). Like the last, but aper- 

 ture very narrow or cleft-like. Outer lip much thickened in the middle. Tithonian. 



Columbellina, d'Orb. ; Cretaceous. Petersia, Gemm. (Fig. 950) ; Tithonian. 



Family 21. Cypraeidae. Gray. 



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

 very large body whorl. Aperture of equal length with the shell, narrow, anteriorly and 



. 946. 



Hippochrenes Murchisoni, Desh. Calcaire 



Grassier ; Damery, near Epernay. 



FIG. 948. 



Columbellaria coral- 

 Una, Quenst. sp. 

 Coral- Rag ; Nattheim. 



FIG. 949. 



Zittelia crassissima, 

 Zitt. sp. Tithonian; 

 Stramberg. 



Fio. 950. 



Petersia costata, 

 Gemm. Tithonian ; 

 Palermo. 



