panamic-pacific pelecypoda 49l 



Explanation of Plate 18 



Figure Page 



1. Pinna rugosa Sowerby 143 



Figure after Reeve, 1858. 



2-2a. Isognomon chemnitziana (d'Orbigny) 149 



Fig. 2, height 22.8 mm, Esmeraldas, Ecuador. PRI 25602; Fig. 2a, 

 length 37 mm. Manta, Ecuador. PRI 25606. 



3-3b. Finctada mazatlanica (Hanley) 147 



All figures of the same shell, length 105 mm. Pearl Islands, Panama. 

 PHI 25603. 



4. Pteria sterna (Gould) 146 



Length 91.4 mm. Lobitos, Peru. P'RI 25604. 



5-5c. Pteria beiliana, new species 146 



All figures of the same shell, length 36.8 mm. Venado Beach, 

 Panama Canal Zone. Coll. Mr. Lee Beil. Holotype, ANSP 218932. 



6. Atrina (Servatrina) manra (Sowerby) 145 



In Academy collection as A. lanceolata (Sowerby) Puerto Pizarro, 

 Peru. ANSP 183947. 



7. Atrina (Servatrina) manra (Sowerby) 145 



Length 240 mm. Cojimenes, Ecuador. PRI 25695. 



