SOUTE AFRICAN MARINE MOLLUSKS. 191 



Family LYONSIDAE. 



Genus LYONSIA Turton. 



LYONSIA, species? 



Cat No. 249877, U.S.N.M., contains two valves of a Lyonsia too 

 poor to be determined, from Port Alfred (Coll. No. 1149). 



Family THRACIDAE. 

 Genus THRACIA Blainville. 



THRACIA, species? 



There are five lots of young Tkracia in the collection of the United 

 States National Museum, all from Port Alfred, but they are too 

 young to be properly determined: Cat. No. 187181, one valve (Coll. 

 No. 732) ; Cat. No. 187186, one valve (Coll. No. 737); Cat. No. 

 249878, two valves (Coll. No. 1150); Cat. No. 249881, two specimens 

 (Coll. No. 1153); Cat. No. 249882, three specimens (Coll. No. 1154). 



Genus CLISTOCONCHA Smith. 



CLISTOCONCHA INSIGNIS Smith. 



There are six lots of this species in the collection of the United 

 States National Museum, all from Port Alfred, as follows: Cat. No. 

 227819, three specimens (Coll. No. 914); Cat. No. 249868, one speci- 

 men (Coll. No. 1140); Cat. No. 249869, one specimen (Coll. No. 

 1141); Cat. No. 249870, one specimen (Coll. No. 1142); Cat. No. 

 249879a, one specimen (Coll. No. 1151a); Cat. No. 249880), two 

 specimens (Coll. No. 1152). 



Order TBLEODE9MACEA. 



Family CRASSATELLITIDAE. 



Genus CRASSATELLITES Kruger. 

 CRASSATELLITES ACUMINATA Sowerby. 



There are three lots of this species in the collection of the United 



States National Museum, all from Port Alfred, as follows: Cat. No. 



186933, one and one-half specimens (Coll. No. 303);.Cat. No. 251017, 



two valves (Coll. No. 1534); Cat. No. 251018, another young valve 



(Coll. No. 1535). 



Genus CUNA Hedley. 



CUNA CONCENTRICA, new species. 

 Plate 47, fig. 3; plate 52, figs. 11, 12. 



Shell minute, thin, bluish white, semi transparent, having an almost 

 triangular outline, with the posteiior dorsal margin quite evenly 

 curved and the anterior slightly concave. Entire surface marked 

 by very regular, strong, threadlike, concentric rings, which are a 



