OP SANTO DOMINGO. 



251 



thinner and in having twice as many ribs. It is possible that perfect sliells may show 

 tubercles over the entire surface, the middle of my single specimen being somewhat 

 worn. , . 



C. (Serripes) bulla. Gabb, n. s. 



Shell sub-circular, thin, compressed, umbones small, posterior side a little more produced than the anterior. 

 Surface marked only by lines of growth. Diameter 1.7 inch. . , ' 



Not unlike C. (>S'.) Groenlandicum, but flatter and more circular. 



C. (Lffivicardium) venustum. Gabb, n. s. 



Shell oblique cordiform, convex ; umbones larger ; anterior end rounded ; posterior obliquely produced ; surface 

 marked in the middle by very numerous minute radiating ribs ; anterior and posterior ends smooth. Length about 

 1 inch. 



jS^earest to C. oblongum, but much shorter, more expanded posteriorly and with 

 much finer ribs. 



C. (Fragum) Ilaitensc. Sby., Quart. Jour., Vol. VI., p. 52, pi. 10, fig. 11, ' 



C. Haiteme. Guppy, Quart. Jour., Vol. XXII., p. 293. ^ ' ' " 



Like C. media, but with much fewer ribs. ' • ■ \ 



CHAMA. Brug. 



C. macrophylla. Chemn., Conch. Cab., Vol. VII., p. 149, pi. 52, fig. 514, 515. 

 C. ar cine 11a. Linn., Syst. Nat., (12 Ed.), p. 1139. 



The fossil specimens are peculiar in that their spines are always small, amounting 

 hardly to more than tubercles. 



LUCINA. Brug. 



L. Jamaicensis. Chemn., sp. 



Venus, id. Chemn., Conch. Cab., Vol. VII., p. 24, pi. 38, fig. 308, 309. 

 L. Antillarum. Rve., Icon., sp., 37. 



L. tigerina. Linn., Syst. Nat., (Ed. 12), p. 1133. ' 

 L. costata. D'Orb, La Sagra, pi. 47, fig. 40, 42. 



L. dentata. Wood, Gen. Conch., 195, pi. 4G, fig. 7. 



For the abundant synonymy of this species, sec Tiyon., Pr. Phil. Acad., 1S72, p. 85. 



L. c r e n u 1 a t a . Con. Foss. Med. Tert., p. 39, pi. 20, fig. 4. 



Fossil in the miocene of Virginia and living on the coast of the United States. 



L. Y a q u e n s i s . Gabb, n. s. 



Shell minute, convex, sub-translucent ; beaks central, prominent ; hinge line deeply excavated under the beaks, 

 sloping, slightly convex behind ; base and ends regularly rounded ; hinge thin, teeth well developed ; internal margin 

 minutely crenulated. Surface marked by small concentric lines. 



About the size of L. crenulata, this shell is much thinner and more globose. It is 

 less excavated in front of the beaks, and the interaal edge is ornamented by much 

 finer crenulations. 



LORIPES. Poli. 



L. e den tula. Liun., Mus. L'lvic, p. 74. 



