CRETACEOUS FOSSILS. 167 



outer lip expanded, biangular, bordered by a thickened margin, 

 the posterior and lateral margins concave, a digitate process at 

 the posterior angle ; anterior angle (not produced ?) ; inner lip 

 expanded over the front of the body whorl, and continued up the 

 spire as high as the canal, very much thickened and longitudi 

 nally striate on the outer margin ; canal and anterior portions of 

 the shell unknown. 



Length, less all of the anterior canal, 1. inch ; width of body whorl, .45 inch ; 

 width, including outer lip, .9 inch. 



From the Shasta Group, Cottonwood Creek, Shasta County. 



A peculiar shell, easily distinguished even in fragments by the regular slope of 

 the spire, the biangular form of the body whorl, the heavy incrustation of the 

 inner lip, and the long, solid posterior canal. The genus, proposed by me in Amer. 

 Jour. Conchology, 1868, page 145, is a strongly characterized member of the Apor- 

 rhaidce, and seems to be the nearest ally of Aporrhais in the Cretaceous, having 

 many of the characters of that genus, and forming the link between it and Anchura; 

 the lip being much more like the latter than the former genus, unless perfect speci 

 mens of the present species should prove, by being bi-digitate, that this is not a 

 constant character. 



H. COSTATA, D. 8. 

 PI. 28, Fig. 48. 



SHELL small, broadly fusiform, spire elevated ; whorls six or 

 seven, angulated in the middle, sloping, and nearly straight above, 

 slightly convex below; above the angle are numerous fine striae, 

 below are five or six subacute revolving ribs, with broad concave 

 interspaces. Aperture broad above, narrowed in front, posterior 

 canal well marked, and curving backwards; outer lip and ante 

 rior canal unknown ; inner lip thinly incrusted. 



Length, less the anterior canal, .47 inch ; width of body whorl, .3 inch. 



From the Martinez Group, Martinez. 



A little shell, strongly characterized by its revolving ribs, and very angular 

 whorls. The posterior canal, in the specimen, reaches to the second whorl above 

 the aperture, and seems to have been attached to the spire still further, before 

 being deflected ; the groove is unusually deep, and the specimen was probably not 

 entirely mature, judging both from this character, and from the thinness of the 

 inner lip, which, in all the other species, is heavily incrusted. 



