FROM PLIOCENE CLAY BEDS IN COSTA RICA. 353 



Limon and Moen, Costa Rica, and living on the Gallapagos Islands A recorapari- 

 son with reference to the Costa Rican fossil confirms my previous determination. 



T. (epidromus) lanceolatum, Kien. 



One beautifully preserved specimen. 



DISTORTIO, Bolt. 



D. siMiLLiMus, Sbj'., sp., Q J. G. S., v. 6, p. 48. 



For synonyms see Tr. Am. Phil. Sac, 1873, p. 212. 



Common in the Miocene of Jamaica and Santo Domingo, but not known 

 recent, unless it should prove to be the same with D. constrictus of the West 

 Coast, from which it seems to present constant points of difference. 



BURSA, Bolt. 

 B. NANA, Sby , Concli. IlL, fig. 6. 



Another Panama species. 

 B. (Lampas) cruentata, Sby. sp.. Conch. Ill , fig. 5. 



A centra] Pacific species. This is the shell which 1 quoted under the incor- 

 rect name of "jTnX commutatum, Dkr." (Tr. Am Phil. Soc, 1874, p. 211), follow- 

 ing an incorrect label in the museum Phila. Acad. Both the Costa Rican and the 

 Dominican fossils agree perfectly with the description and figures, and with recent 

 specimens in the Academy's museum. 



NASSA, Mart. 

 N. Carib^a, Gabb, n. s. 



Shell moderate in size, robust ; heavily costate ; spire elevated ; whorls, three 

 nuclear, smooth ; seven others, abruptly truncated on top, but not angular ; sides 

 convex. Surface marked by large rounded longitudinal ribs, placed a little 

 obliquely and with interspaces equal in size to the ribs ; these, about thirteen or 

 fourteen in number, are crossed by numerous small, sharply defined revolving ribs, 

 which are of the same size on the ribs and in the intervening spaces. Mouth two- 

 fifths of the length of the shell, regularly elliptical; callus thin, not much expanded; 

 a single linear tooth posteriorly and a strong fold on the end of the columella; 

 outer lip heavily thickened externally, internally striate; anterior end of the aper- 

 ture strongly twisted, with the characteristic external groove deeply impressed. 



About the size of N. trivittata, Say. This species is amply distinguished by 

 its shorter and more robust form, its stronger sculpture and the thickening of the 

 outer lip. 



73 



