OF SANTO DOMINGO. . ' ■ 247 



SILIQUA. Muhlf. . " 



S. s u b 83 q u a 1 i s. GaLI), n. s. ^ ■ - , . ■ 



Shell small, translucent, narrow, beaks central, base straight, ends nearly equal ; surface polished ; internal rib 



small, oblique. Length 1 inch. 



Differs from S. costata in being more slender and in tlie beak being central. 



BOTHROCORBULA. Gabb, n. gen. 



Shell like Corbula in form and hinge, but diflering in having a deep lunular pit in advance of the beaks, pene- 

 trating and almost passing through the hinge plate. 



I have carefnlly examined almost all of the living and many fossil species of Cor- 

 hula, and can find in none the slightest trace or rndiment of a lunnle ; w^hile this 

 shell has it deeper than it occurs in any other form except in Here {JVoh.) of the 



B. V i ni i n e a. Guppy, sp. 



G.viminea. Guppy, Quart. Jour. Gcol. Soc, Vol. XXII., p. 293, pi. 18, fig. 11. 



CORBULA. Brug. ' - • : . .■ 



0. disparilis. D'Orb., La Sagra, Cuba, pi. 27, fig. 1-4. . ' ' ■ ' ^ 



G. vieUi. Guppy, Quart. Jour., Vol. XXII., p. 580, pi. 2G, tig. 8. ' , 



C. contract a. Say., Jour. Phil. Acad., 1 Ser., Vol. XL, p. 312. • . . . 

 C. D o m i n i c e n s i s. Gabb, n. s. 



Shell large, thin, nearly equivalve, beaks central, valves moderately convex, no lunule, posterior end produced 

 into a sharp angle ; a narrow flat space rftnning from the beaks to the angle. Surface marked by numerous moderately 

 fine concentric ribs. About the size of G. viminen, this species is without the lunular pit, is much more finely 

 sculptured, flatter and more produced posteriorly. In this latter character it also differs from G. crnssa, which seems 

 to be its nearest ally. - 



C. Lavaleana. D'Orb , La Sagra, Cuba, ph 27, fig. 9-12. . 



Abundant. 



NEJEROMYA. Gabb, n. gen. . , . .- 



Shell thin, translucent, in shape api>roacliing PJioladomya, ends closed ; liinge with a prominent tooth in tlie 

 right valve, articulating behind a smaller similar one in the left valve. An anterior and posterior lateral tooth in 

 each valve. Mantle margin without a sinus. 



This genus, in its thin character and minute hinge, is closely allied to PJioladomya, 

 Thetis and Nemra, but difters from all in the details of the hinge. JVea^ra has no 

 cardinal tooth, but in its place a cartilage pit on each valve. It has a single posterior 

 tooth, while this genus has the anterior equally Avell developed. In having corres- 

 ponding teeth in both valves it difters from Thetis, while its well specialized hinge 

 and its closed ends distinguish it from Pholadomya. 



N. quad rata. Gabb, n. s. 



Shell small, rounded, sub-quadrate ; beaks posterior; anterior end produced, rounded, and slightly narrowed ; 

 posterior end broadly rounded ; base nearly straight. Surface polished, marked only by minute lines of growth. 

 Length .3 inch, height .23 inch. 



A beautiful little translucent shell which looks like a small Fholadomija. 



