SOUTH AFRICAN MARINE MOLLUSKS. 185 



Genus PHILOBRYA Carpenter. 



PHILOBRYA AFRICANA, new species. 

 Plate 46, figs. 1, 2. 



Shell small, translucent, white, broadly triangular, with the beaks 

 at the apex of the triangle. Dorsal edge slightly curved, ventral 

 somewhat concaved; posterior portion well rounded. The junction 

 of the posterior and dorsal edges form somewhat of an angle and give 

 the shell an alate aspect. The external surface of the shell is marked 

 by fine concentric lines of growth and numerous, exceedingly fine, 

 irregularly radiating, hair-like streaks which give to the surface a 

 silky luster. 



The type and another specimen, Cat. No. 187154, U.S.N.M., come 

 from Port Alfred (Coll. No. 70 1 ) . The type measures : Length, 5 mm. ; 

 diameter, 4 mm. 



In addition to these, the United States National Museum contains 

 five lots, all from Port Alfred, as follows: Cat. No. 227811, six valves 

 (Coll. No. 906); Cat. No. 227812, five valves (Coll. No. 907); Cat. 

 No. 249841, two specimens (Coll. No. 1113); Cat. No. 251001, one 

 valve (Coll. No. 1518); Cat. No. 251007, one valve (Coll. No. 1524). 



Family PTERIIDAE. 



Genus MARGARITIPHORA Muhlfeld. 



MARGARITIPHORA NATALENSIS Jameson. 



Cat. No. 17225, U.S.N.M., contains a specimen from the Cape of 

 Good Hope. 



MARGARITIPHORA CAPENSIS Sowerby. 



Cat. No. 186914, U.S.N.M., one specimen from Port Alfred (Coll. 

 No. 284). 



Family OSTREIDAE. 

 Genus OSTREA Lamarck. 



OSTREA ALGOENSIS Sowerby. 



Cat. No. 175, U.S.N.M., contains a specimen collected by William 

 Stimpson on the North Pacific Exploring Expedition at Simons Bay, 

 on rocks at low water. In addition to this, the United States National 

 Museum contains 14 lots from Port Alfred, as follows: Cat. No. 

 187163, four specimens (Coll. No. 710); Cat. No. 187164, one speci- 

 men (Coll. No. 711); Cat. No. 187165, eight valves (Coll. No. 712); 

 Cat. No. 249833, two young specimens (Coll. No. 1105); Cat. No. 

 250981, one specimen (Coll. No. 1498); Cat. No. 250982, two valves 

 (Coll. No. 1499); Cat. No. 250983, one specimen (Coll. No. 1500); 



