CRETACEOUS FOSSILS. 259 



Texas, and that by Conrad in the Mexican Boundary Beport, in having the dorsum 

 distinctly channelled or flattened, and bordered by two angles, and in having the 

 sides variously undulate or even subcostato. I have seen the flattened dorsum, in 

 Texan specimens ; and the undulations of the sides, on the specimens before me, 

 show by their variability that this is a character of no specific value. The septum 

 is identical with the published figures. 



FUSUS, Lam. 

 P. Mexicanus, n. s. 



PL 35, Fig. 2. 



Shell small, elongate fusiform ; spire high, whorls five or six, 

 angulated, top sloping; suture undulated. Surface ornamented 

 by about ten large radiating ribs, crossed by numerous prominent 

 revolving lines with broad interspaces ; the longitudinal ribs com- 

 mence at the suture and, on the body whorl, disappear about the 

 middle. Aperture broad and biangular posteriorly, narrowed in 

 advance; outer lip simple, inner lip incrusted; canal produced. 



Length (both ends broken), .75 inch. 



A peculiar species, having no near allies either in California or Texas. 



LUNATIA, Lam. 

 L. Pedernalis, Roem., sp. 



PL 35, Fig. 3. 



(Natica Pedernalis, Boem. ; Kreid. Tex., p. 43, pi. 4, fig. 1.) 



Dr. Boemer seems to have been acquainted with this species only through in- 

 ternal casts, one of which he figures as above. I am fortunate in having had 

 the opportunity of examining some half a dozen specimens retaining all the shell. 

 The species is very thin, and nearly all have suffered more or less distortion. The 

 specific characters are as follows. 



Shell large, ovate, thin ; spire moderately produced ; whorls 

 five and a half, rounded; suture distinct. Aperture elongate 

 ovate, acute behind, rounded in advance ; outer lip simple, inner 



