DESCRIPTIONS OF CARIBBEAN MIOCENE FOSSILS. 345 



C. (l^vicardium) Milleri, Gabb, n. s., PI. 44, fig. 18. 



Shell small, convex, rounded subquadrate, nearly equilateral; beaks central; 

 rather prominent, incurved, approximated, and with apex pointed very slightly 

 forward. Anterior end and base broadly rounded; posterior end very faintly 

 truncated. Surface marked by a faint cross-lining of radiating lines and those of 

 growth, nearly microscopic in its fineness. Internal margin minutely crenulated. 



Figure. Slightly magnified. 



Given to me by Mr. S. Miller, who found it at Sapote, Costa Rica. 



LUCINA, Brag. 

 ?L. SP. INDET., PI. 44, fig. 19. 



A single internal cast from Sapote, too imperfect for positive determination. 

 It shows no specific character except outline, and none generic except the posterior 

 umbonal depression common in this genus. 



CRASSATELLA, Lam. 

 C. MACTROPSis, Con., sp., PL 44, fig. 20. 



Gratelupia id., Con., Pacific R. R. Report, vol. 5, p. 328, PL 6, f. 54. 

 C. Antillarum? Gabb, Tr. Amer. Philos. Soc, voL 15. 

 Not id., Rve., ZooL Proc, 1842, p. 44, Icon. sp. 8. 

 C. Reevei, Gabb (Provis. name), Tr. A. P. S., v. 15. 



When I published this species as coming from Santo Domingo, on account of 

 deficient material I referred it provisionally to Reeve's species; at the same time 

 doubting the determination so much that I proposed a new name if further mate- 

 rial should confirm my doubts. But a solution comes in from another source. The 

 hardly recognizable description and figure of Conrad, and the unpardonable generic 

 reference has at last been made out. It was one of the last pieces of assistance the 

 old gentleman rendered me before his death. The difi"erence in shape of the pos- 

 terior end is sufficient to distinguish it from Reeve's species. I have two speci- 

 mens from Sapote, the longest of which is figured, natural size 



PINNA, Linn. 

 P. SEMiNUDA, Lam, 



Abundant in the brown shale on the roadside at Sapote, forming masses. The 

 shell is now living on the coast from Texas to Georgia. 



ARCA, Linn. 



A. GRANDis, Brod. and Sby., ZooL Journ., v. iv. 

 A. Patricia, Sby., Guppy. 



A. very like grandis, Moore, Qnart.^ourn. Geol. Soc, v. 9. 

 A. Chiriquensis, Gabb, Proc. Phila. Acad., 56Y, 1860. 

 72 



