688 SYSTEMATIC PALEONTOLOGY 



Type Locality. Eufaula, Alabama. 



Shell rather small and thin for the genus, transversely ovate in outline, 

 conspicuously compressed; lunule and escutcheon not differentiated: 

 umbones small, flattened, anterior, the apices acute, prosogyrate and pro- 

 jecting slightly beyond the dorsal margin; umbonal angle not far from 

 140 ; anterior dorsal slope less gentle, more uniform, and less produced 

 than the posterior, merging gradually into the anterior lateral margin; 

 posterior dorsal margin produced more or less gibbous, very thin and sharp 

 by reason of the bevelling along its inner surface ; posterior lateral margin 

 vertically truncate ; base line obliquely arcuate, much more strongly so in 

 front than behind; external surface striated "with a modified incremental 

 sculpture which is sharp and regular in the immediate vicinity of the 

 umbones, but which becomes less sharp and less regular away from them ; 

 resting stages increasingly numerous toward the base line ; ligament sub- 

 marginal, opisthodetic ; cardinals three in number in each valve, radiating 

 fan-like from beneath the umbones ; anterior cardinal of right valve sharp, 

 elevated, laminar, the middle cardinal broad, low, asymmetrically cuneate, 

 the posterior cardinal even more elevated than the anterior and, like it, 

 thin and laminar, though feebly reinforced upon its anterior surface; 

 anterior cardinal of left valve rather heavy, expanding ventrally, the 

 middle cardinal elevated along its posterior margin, the posterior, thin, 

 sharp, laminar and not very prominent; laterals not developed, though 

 there is a minute and irregular depression a little less than half-way down 

 the posterior dorsal margin of the left valve, which is occupied by a cor- 

 responding elevation in the right ; muscle scars rather small and obscure, 

 the anterior elongated, the posterior semi-elliptical, placed high up under 

 the extremities of the hinge plate ; pallial line simple but truncated pos- 

 teriorly, far distant from the base line ; inner ventral margins simple. 



Cyprimeria depresssa Conrad might more properly have been named 

 compressa, since the extreme compression of the valve is the most striking 

 diagnostic of the species. It is the smallest member of the genus reported 

 from the area under discussion. The only resemblance sufficiently strik- 

 ing to cause confusion is that with the larger, less compressed C. cretacea 



