FROM THE TERTIARY OF VIRGINIA. 15 



growing for awhile, and some are minutely wrinkled. The cicatrices are deep and well 

 denned. The whole shell is remarkably globose. 



This species agrees pretty well with the description of S. trisulcata, Conrad, but that 

 shell is said to be "obovate," while ours is very rotund. It is also closely allied to some 

 of its congeners from Claiborne. 



FAMILY CONCHIM. 



GENUS ASTARTE. 



A. LINEOLATA, PL. 34. FlG. 20. 



A. testa triangulari, pene czquilaterali, injlata, crassa, striatd; striis crcbrissimis, rotundatis, conccntricis; margine basali 



sub-curvato; natibus elevatis, acuminatis; lunula valde clongatd; dentibus magnis, valde divetgentibus; margine interno crenulato. 



Shell triangular, almost equilateral, inflated, thick, striate; striee concentric, very numerous, rounded; basal margin 



somewhat curved; beaks elevated, acuminate; lunule much elongated ; teeth large, very divergent ; internal margin 



crenulate. 



Diam. .15. Length .18. Breadth .21 of an inch. 



Remarks. The striae are very regular, minute, and about fifty in number, on a full- 

 grown specimen now before me. The lunule is unusually long and rather broad. The 

 beaks are elevated and produced. 



I, at first, regarded this as a young specimen of A. concentrica, Conrad, but the 

 crenulations on the inner margin prove it to be full-grown. In size it approaches the A. 

 lunulata, Con., but the strise are much smaller and more numerous, and the shell is 

 more inflated. 



GENUS CYTHEREA. 

 C. ELEVATA, PL. 34. FIG. 21. 



C. testa ovatu, transversd, inatquilaterali, postice subtruncatd, antice rotundato-angulatu, injlata, crassa, nitente, substriatd; 

 striis concentricis, minimis, media obsolctis; margine basali curvato; margine dorsali angulato; natibus elevatis, prominentibus; 

 dentibus magnis, quorum uno bifido. 



Shell transverse, ovate, inequilateral, subtruncate posteriorly, rounded-angular anteriorly, inflated, thick, shining, 

 substriate; striae concentric, very small, obsolete in the middle; basal margin curved; dorsal margin angular; beaks 

 elevated, prominent; teeth large, one bifid. 



Diam. .19. Length .28. Breadth .32 of an inch. 



Remarks. There are no very decided characters about this shell, yet I cannot refer it 

 to any known species. When young, its form is more longitudinal* It is more allied to 

 C. convexa, Say; than to any other shell. 



C. SPHJERICA, PL. 34. FIG. 22. 



C. testa rotunda, aquilatcrali, globosd, tenui, l<evi, politd; margine dorsali curvato; natibus elevatis, prominentibus, rectis 

 lunula minima, lanceolatd; dentibus parvis. 



Shell rotund, equilateral, globose, thin, smooth, polished; dorsal margin curved ; beaks elevated, prominent, straight; 

 lunule very small, lanceolate; teeth small. 



Diam. .18. Length .19. Breadth .20 of an inch. 



D 



