panamic-pacific pelecypoda 527 



Explanation op Plate 54 



Figure Page 



1-ld. Fetricola (Petricola) denticnlata Sowerby 311 



Fig. 1, enlargement of hinge; Figs, la, lb, a right valve, length 29.4 

 mm.; Fig. Ic, length 31 mm., Santa Elena, Ecuador. P'RI 25770; Fig. 

 Id, length 23.3 mm. Galeras, Ecaudor. PRI 25771. 



2-2a. PetricoLa (Petricola) robusta Sowerby 315 



Fig. 2, enlargement of hinge; F^g. 2a, length 24.8 mm. Extracted from 

 a burrow in a shell of Spondylus. Montanita, Ecuador. PRI 25772. 



3-3b. Petricola (Petricolaria) parallela Filsbry and Lowe 31G 



Fig. 3, enlargement of hinge; Fig. 3a, 3b, length 41.4 mm. Bucaro, 

 Panama. PRI 25773. 



4-4b. Petricola (Petricolaria) conciima Sowerby 



Figs. 4, 4a, length 19 mm.; Fig. 4b, length 20.5 mm. Esmeraldas, 

 Ecuador. PRI 25774. 



5-5a. Petricola (Petricolaria) cognata C. B. Adams 316 



Copied after Pilsbry and Lowe, 1932. Length 23 mm. Panama. Holo- 

 type. MCZ. 



6. Nioche (Nioclie) asperrima asperrima (Sowerby) 307 



Right valve, length 42.5 mm. Guaymas, Mexico. Coll. L. Brand. PRI 

 25775. 



7. Petricola (Naraiiio) cliarapota, new species 317 



Length 30 mm. Charapota, Ecuador. Holotype, ASNP 218907. 



