INVEETEBKATE PALAEONTOLOGY. 



147 



recent typical species, presenting in this respect, apparently, a generic 

 character, since in all of the more gibbous, oblique Cretaceous 'species more 

 properly falling into the genus Veniella (— Venilia) thai 1 have bad an 

 opportunity to examine, these two muscular scars are clearly disconnected. 

 The pallia! line is well defined, and a little straightened or truncated just 

 beneath the posterior muscular scar. 



Locality and position. — Mouth of Heart River; from the upper part 

 of the Fox Hills group, or No. 5 of the Cretaceous series. 



Cyprina ovata, var. comprcssa. 

 Plate 30, fig. 11. 

 Cyprina compressa, Meek and Hayden (May, 1857), Proceed. Acad. Nat. Sci. Pkilad., IX, 144. 



Since describing this form as a distinct species, I have been led by- 

 further comparisons to regard it as probably only a variety of C. ovata, with 

 which it was found associated. It agrees with that species in all respects, 

 excepting in the greater elevation and more nearly central position of its 

 beaks, which are also a little less oblique. These differences, however, are 

 probably hardly of specific importance, especially since some fragments 

 among the collections apparently indicate intermediate gradations of form. 

 No good specimens of the more elevated form have yet been found. 



Genus VENIELLA, Stoliczka. 



Synon. — Venilia, Morton (1834), Synopsis Org. Rein. Cret. Form. U. S., G7. — Conrad (.1854), Jonr. Acad. 

 Nat. Sei. Philad., II, 275 ; and ( 1860), ib., IV, 282 ; also (1&71), A. M. Jonr. Conch., VI, 74.— 

 Meek and I [ayden (1857 ). Proceed. Acad. Nat. Sci., IX, 144— Gabb (1861 ), ib., 364.— Meek 

 (1864), Smithsonian Check-List Cret. Foss. N. Am., 13 (not Venilia, Duponchel, 1S29, 

 or of Alder and Handcock, 1844). 



Cyprina (sp.), d'Orbigny I 1843), Paleont. Fr., Ill; and (1850), Prodr. de Paleont.. II.— Stoliczka ' 

 (1870), Paheont. Indica, III, 197 and 198 (not Lam. 1812). 



Veniella, Stoliczka (1870), Pal. Ind., Ill, 189. 



Venilieardia, Stoliczka (1870), ib., 190 (as a subgenus of Veniella). 



Ehjm. — Venilia, a mythological name. 

 Type. — Venilia Conradi, Morton. 



Shell transversely ovate-oblong, trapezoidal or subquadrate, generally 

 very gibbous, and distinctly inequilateral, with the posterior umbonal slopes 

 elevated and angular, or prominently rounded, from the beaks to the posterior 

 basal extremity, to which they impart a more or less angular outline; lice 

 margins closed, and smooth within; beaks gibbous, very oblique, strongly 





