232 Bulletin 29 398 



and was erroneously referred by Guppy to Erycina tensa. The 

 type locality is Manzanilla, Trinidad. Also found at Bowden 

 and in the Trinidad and Costa Rican Pliocene. 



Localities. — (Exp'd '16) Bluff 2, Cercado de Mao; Zone 

 I, Rio Cana at Caimito. 



Corbula (Cuneocorbula) dominicensis Gabb 



Plate 39, Figures 14, 15 

 Corbula Dominicensis Gabb, Trans. Amer. Phil. Soc, vol. 15, p. 247, 



1873- 

 Corbtila (Cuneocorbula) Dall, Trans. Wagner Inst. Sci., vol. 3, pt. 

 4, p. 847, 1898. 



Shell about the size of Bothro corbula viminea but without 

 the lunular pit, more finely sculptured, flatter and thinner. The 

 two valves are very nearly alike, moderately convex, posterior 

 end angulated, beaks sub-central. Length of left valve 13.5, alti- 

 tude 9, semidiameter 4 mm. This species has not heretofore 

 been figured but our shells agree with Gabb's description. 



Locality. — (Exp'd '16) Sandy clay and Zone H, Rio Cana 

 at Caimito. 



Corbula {Citneocorbula) cercadica, n. sp. 



Plate 39, Figures 16, 17 



Cf. Corbula Lavaleana Gabb, Trans. Amer. Phil. Soc., vol. 15, p. 247, 

 1873. Not C. Lavaleana d'Orbigny 1845. 



Thousands of valves of a small Corbula were collected by 

 us at Cercado where it is extremely abundant. This is probably 

 the species of which Gabb also found a large number and referred 

 to the recent C. Laraleana d'Orbigny. But it is smaller than 

 that species and differs markedly in its broader and much less 

 elevated beaks. Our shell is very finely concentrically sculp- 

 tured and some specimens show faint radial stria? as in C Lava- 

 leana. From the Bowden C sericea Dall, our shell differs in be- 

 ing less short and high, proportionally longer and in lacking the 

 profound sulcation anterior to the umbonal ridge characteristic 

 of the Bowden shell. The valves of this very abundant Domini- 

 can species are discrepant, the left smaller and shorter, not 



