506 AXEL A. OLSSON 



Explanation of Plate 33 



Figure Page 



1-lb. Pseudochama panamensis (Reeve) 225 



Figs. 1, la, same specimen, greatest length 68 mm; Fig. la, shows 

 the large attachment surface of the right valve.; Fig. lb, inside 

 of attached valve, pure white in color, length 68 mm. La Libertad, 

 Santa Elena, Ecuador. PRI 25657. 



2-2a. Chama pellncida Sowerby 225 



Exterior and interior of attached valve, height 55 mm. Bayovar, 

 Peru. PRI 25658. 



3. Chama ecliinata Broderip 224 



Combined length of both specimens, 46.8 mm. Concepcion Beach 

 near Las Tablas, Panama. PRI 25659. 



4-4a. Codakia (Codakia) distinquenda (Tryon) 217 



Inside of valve and enlargement of hinge, length 76 mm. Isla la 

 Plata, Ecuador. PRI 25660. 



5. Kellia suborbicularis (Montagu) 231 



Length 2.5 mm. Punta Centinella, Santa Elena, Ecuador. PRI 25661. 



6-6b. Aligeiia cokeri Dall 234 



Fig. 6, enlargement of hinge.; Figs. 6a, 6b, length 6.6 mm. Venado 

 Beach, Panama Canal Zone. PRI 25662. 



7-7a. Polymesoda (Egeta) aiiomala (Deshayes) 194 



A young shell showing the pronounced, pointed posterior end and 

 the almost entire pallial line in the interior. Tumaco, Colombia. 



