GASTROPODA— NERITID&—FISSURELLID2E. 707 



338. N. pisum Meek. (Fig. 10 17, h, i.) Cretacic. 

 Small (height 0.22 in.), smooth, with four denticles on inner lip, 



in groups of two. 



Colorado of Coalville, Utah. 



XCVII. Velatella Meek. 

 Neritoid shells, depressed-convex above, flattened on apertural 

 side, with large inner lip ; enlargement of body whorl such as to 

 give the shell a patelliform aspect ; with minute, slightly incurved 

 apex. Cretacic. 



339. V. patelliformis Meek. (Fig. 10 18, a, b.) Cretacic. 



FlG. IO 1 8. a, b, Velatella patelliformis ; c, V. carditoides ; d-h, V. baptista. (After 



White, U. S. G. S.) 



Small, thick, oval, almost perfectly bilateral ; inner lip broad 

 and thick, faintly denticulate, extending more than half the length 

 of the base of the shell ; surface with growth lines. 



Lower Colorado of Coalville, Utah, and Bear River, Wyoming. 

 Common. 



340. V. carditoides Meek. (Fig. 10 18, c.) Cretacic. 

 Surface with well-marked radiating rib-like spirals. 



Upper Colorado, Coalville, Utah. 



341. V. baptista White. (Fig. 1018, d-h.) Cretacic. 

 Enrolled apex prominent ; surface smooth except for color 



bands, which are sometimes preserved. Edge of inner lip smooth. 

 Laramie of Wyoming and the region of the Bow and Belly 

 rivers, Canada. 



Family Fissurellid^e Risso. 

 XCVIII. Emarginula Lam. 

 Subconic shells with submedian or posterior apex, and anterior 

 marginal slit. (These characters are also those of young Fissu- 

 ridea.) Carbonic-Recent. 



