39 1 Dominican Fossils — Maury 227 



specimen is imperfect and we lack shells of constricla for compar- 

 ison ; but while it is of the same general type it is very doubtful 

 if the fossil is really identical with constricta. 



Locality. — (Exp'd '16) Zone I, Rio Cana at Caimito. 



Macoma (Psammacoma) yaquensis, n. sp. 

 Plate 39, Figure 8 



Shell rather small, thin, compressed, beaks low, pointed ; 

 anterior end longer than the posterior, rounded ; posterior end 

 feebly angulated, bluntly terminated ; surface smooth except for 

 fine growth-lines ; cardinal teeth sharp, hinge delicate. Length 

 17.5, altitude 9.5, semidiameter 1.5 mm. This species is is near- 

 est to M. tracta Dall from Chipola, Florida and Bowden, but is 

 nearly a third larger and differs somewhat in form. 



Locality. — (Exp'd '16) Bluff 3 Cercado de Mao. 



Macoma (Cymatoica) hispaniolce, n. sp. 

 Plate 39, Figure 9 



Shell small, inequivalve, rostrate and gaping posteriorly ; 

 rounded and gently convex anteriorly ; left valve slightly shorter 

 than the right, hardly sulcate posteriorly, shortly rostrate, mark- 

 edly truncate ; right valve strikingly rostrate and flexuous pos- 

 teriorly ; both valves with feeble, irregular concentric sculpture 

 except on the posterior part of the right valve where there are 

 about eight short, crested waves. Length 10, altitude 5.50, 

 semidiameter 1.50 mm. The species most resembling our shell is 

 M. Vendryesi Dall from Bowden. 



Locality. — (Exp'd '16) Bluff 3, Cercado de Mao. 



Genus Semele Schumacher 



Semele Claytoni, n. sp. 

 Plate 35, Figure 9 



Shell very large and fine, of the same general type as ►S. 

 perlamellosa Heilprin and 5*. Leana Dall, and in outline some- 

 what intermediate between these species. It is less elliptical and 



