UNDOUBTED TERTIARY SPECIES. 187 



Genus CAEINIFEX, Binney. 



Subgenus VORTICIFEX,* Meek. 



(Proceed. Acad. Nat. Sci. Pbilad., Ap., 1870, C9.) 



This type differs from Carinifex proper in having no traces of the 



revolving carinse seen on the typical species of that genus, and in having 



very strongly defined costse of growth on young examples. It is also a 



thicker shell, with a smaller umbilicus. The first of the following species 



is regarded as the type of the subgenus. The group seems to be related to 



Choanomphalus^ Gerstfeldt; but, as that genus was founded on minute or very 



small shells, quite similar to Valvata, it is not very probable that our type 



is congeneric. 



Carinipex (Vobticipex) Binneti, Meek. 



Plate 17, figs. 11, 11 a. ^ 



Carinifex Bhineyi, Meek (1870), Proceed. Acad. Nat. Sci. Philad., 59. 



Shell attaining a large size, depressed-subglobose in form ; spire scarcely 

 rising above the body- whorl ; umbilicus large, but rapidly contracting 

 within; volutions about three and a half, increasing very rapidly in size ; 

 those of the spire a little convex ; last one forming more than nine-tenths 

 the entire bulk of the shell, widest above, and produced below so as to form a 

 prominent ridge, or subangular margin around the widely-excavated umbili- 

 cal region ; all without revolving carinse ; aperture large, obovate, being 

 widest above and narrowed abruptly to a subangular termination below ; 

 lip remarkably oblique, apparently very slightly reflexed, and strongly 

 produced forward above. Surface marked with extremely oblique lines of 

 growth, which apparently sometimes form little regular costse. 



Height, 0.59 inch; breadth, 1 inch; height of aperture, about 0.50 inch; 

 breadth of aperture, 0.54 inch. 



This species differs too widely in nearly all of its characters to require 

 comparison with C. Newherryi, the typical and only known living species 

 of true Carinifex, which it also exceeds in size. 



All of the specimens of this species in the collection are incrusted by a 

 laminated, smooth, calcareous deposit that has to be removed before the sur- 



* This name was wrongly printed Vortifex in the Proceedings of the Academj. 



