182 BULLETIN 91, UNITED STATES NATIONAL MUSEUM. 



Genus ARCA Lamarck. 



ARCA ACUMINATA Krauss. 



Cat. No. 187158, U.S.N.M., one specimen from Port Alfred (Coll. 

 No. 705). 



Genus FOSSULARCA Cossmann. 



FOSSULARCA GIBBA Krauss. 



Cat. No. 186921, U.S.N.M., one specimen from Port Alfred (Coll. 

 No. 291). 



FOSSULARCA GRADATA Broderip and Sowerby. 



Cat. No. 187155, U.S.N.M., contains one specimen and three valves 

 of this species from Port Alfred (Coll. No. 702). 



Genus BARBATIA (Gray) Adams. 



BARBATIA ALFREDENSIS, new species. 

 Plate 46, figs. 9, 10. 



Shell rhomboidal. Surface covered with a thick, dark brown epi- 

 dermis from which project numerous imbricating scales. The 

 umbones are situated in the anterior third of the entire length of the 

 shell. The hinge line is very slightly arcuated, the ventral margin 

 usually incurved. Anterior end much narrower than the broad 

 posterior end. Entire surface marked with numerous fine radiating 

 riblets which are crossed by concentric lines of growth rendering the 

 sculpture of the surface somewhat reticulated. The interior of the 

 shell is bluish white, excepting that portion which lies dorsal and 

 posterior to a hue passing from the umbones to the posterior ventral 

 margin, which is chestnut brown. 



The type and three specimens, Cat. No. 186922, U.S.N.M., come 

 from Port Alfred (Coll. No. 292). The type measures: Length, 34 

 mm.; height, 18 mm.; thickness, 12.5 mm. 



This is what has probably been listed as Area obliquata Gray, a 

 Philippine Island species, which differs from the present species by 

 its much larger size, detailed sculpture, and color. 



BARBATIA, species? 



Cat. No. 18804, U.S.N.M., contains a specimen from Natal which 

 we are unable to refer to any of the known species, but which is too 

 poor to serve for a diagnosis. 



BARBATIA, species? 



Cat. No. 187157, U.S.N.M., contains six valves of a Barbatia from 

 Port Alfred, which we are unable to refer to any of the described 

 species, but is too poor to serve for a diagnosis (Coll. No. 704). Cat. 

 No. 249850, U.S.N.M., contains six additional valves of the same 

 species, in the same condition, from the same place (Coll. No. 1122). 



