1855.] 259 



CRASSATELLA, Lam. 



C. flezura, PI. xiv., fig. 7. Trapezoidal, inequilateral ; ventricose medially ; 

 slightly contracted anteriorly, and more so posteriorly ; umbonal slope angulated 

 and prominent ; whole surface with concentric prominent lines, some of which 

 bifurcate anteriorly; inner margin crenulated. 



Approaches C. protezta, Con., but has the strias over the whole disk, the car- 

 dinal teeth more compressed ; inner margin with larger crenulations, &c 



GLOSSUS. 



G. filosus, PI. xiv., fig. 8. Orbicular, ventricose, with radiating lines, unequal, 

 medially flattened, and towards the ends angulated ; concentric lines microscopic, 

 series of cardinal teeth uninterrupted, generally large and prominent. 



Allied to G. stamineus, Con., but very distinct. 



OSTREA, Lin. 



O. trigonalis, PI. xiv., fig. 10. Triangular, fiat, sui face irregular, withsome 

 indistinct radiating lines; muscular impression obliquely suboval, situated nearer 

 the summit than the base; margin somewhat ascending, submargin carinaced. 



A single imperfect upper valve is all that I have seen of this shell, but it is 

 widely different from any other Eocene species known to me. 



PECTEN, Lin. 



P. nuperus, PI. xiv., fig. 11. Suborbicular, ventricose, with about twenty- 

 three angular, prominent ribs, crossed by fine closely-arranged wrinkled lines; 

 ears finely striated obliquely. 



A single valve with the ears broken is all of this species in the collection. 



UMBRELLA. 



77. pla?iulata, PI. xiv, fig. 1. Suboval, flattened, surface undulated, rising a 

 little towards the apex, which is prominent and acute, and situated much nearer 

 to one side and nearer to one end ; lines of growth conspicuous; inner side with 

 a very large suboval cicatrix, with radiating interrupted lines. 



This fine species is the only one yet known in North America. Two speci- 

 mens occur, one of which is marked with some hair-like brown radiating lines, 

 both internally and externally. 



CAPULUS, Mont. 



C. Am-ericanus, PI. xv., fig. 1. Obliquely ovate, longitudinally contracted on 

 one side ; lines of growth profound ; summit very oblique ; apex profoundly 

 prominent, acute, curving towards the base and projecting far beyond the basal 

 margin ; aperture obtusely oval or suborbicular. 



TROCHITA, Schum. 



T. alta, PI. xv., fig. 3. Conic, elevated, with three or four transverse undu- 

 lations ; radii prominent, rounded, very irregular, interrupted, somewhat tuber- 

 culated; vertex central, spiral, somewhat prominent. 



CLAVELLA, Swains. CLAV1L1THES, Swains. 



1. C. humerosa, PI. xv., fig. 2. Fusiform, volutions eight? rounded; body 

 whorl and penultimate entire, the others with broad rounded ribs; whorls cari- 

 nated below the suture and with revolving lines, most prominent towards the 

 apex; body whorl and penultimate, channelled above and contracted near the 

 summit ; body whorl angulated inferiorly ; beak long and straight. 



2. C. varicosa, PI. xvi., fig. 7. Fusiform, spire and beak elongated; whorls 

 nine, with distant, rounded, thick ribs and with revolving acute lines, which are 

 obsolete or less prominent on the ventricose portion of the body w horl ; papillated 

 apex formed of three volutions; columella nearly straight, and with microscopic 



ongitudinal lines. 

 C. Mississippie?i$is, PI. xvii., fig. 8, is probably the same species. 



