556 axel a. olsson 



Explanation of Plate 83 



Figure Page 



1-la, Cyathodonta tumbezensis, new species 460 



Fig. 1, length 38.2 mm.; Fig. la, enlargement of a small section 

 of the surface. Tumbez, Peru. Holotype, ANSP' 218952. 



2-2b. Cyathodonta undulata pemriana, new subspecies 459 



Fig. 2, length 113 mm., Puerto Pizarro, Peru.; Fig. 2a, enlargement 

 of a small section of the surface.; Fig. 2b, length 25.5 mm., 

 Tumbez, Peru. Holotype, ANSP 218953. 



3. Cnspidaria (Cardiomya) ecuadoriana, new species 465 



Length 8.4 mm. Galeras, Ecuador. Holotype, ANSP 218954. 



4-4a. Thracia anconensls, new species 458 



Length 34 mm. Point Ancon, Santa Elena, Ecuador. Holotype, ANSP 

 218955. 



5. Entodesma (Agriodesma) sechnrana Pilsbry and Olsson 468 



Figure after Pilsbry and Olsson, 1935. Length 68 mm., Bayovar, 

 Peru. Holotype, ANSP* 164624. 



6-6a. Cnspidaria (Cardiomya) costata (Sowerby) 465 



Fig. 6, length 7.3 mm., Santa Elena, Ecuador. P"RI 25944A; Fig. 

 6a, length 7.5 mm., Manta, Ecuador. PRI 25944B. 



7-7a. Thracia colpoica Dall 458 



Right and left valves, length 17 mm., Tumbez, Peru. PRI 25945. 



8. Poromya (Dermatomya) equatorialis Dall 467 



Sta. 2793, near Galapagos Islands, in 791 fms. USNM. 



9. Periploma (Periploma) teevani Hertlein and Strong 463 



Figure after Hertlein and Strong, 1946. Tangola-Tangola Bay, 

 Mexico. Depth 30 fms. 



10. Poromya (Poromya) perla Dall 466 



Sta. 6673, Ballenas Lagoon. Lower California. USNM. 



11. Plectodon scaber Carpenter 



Catalina Island, California. 



12. PythJnella snblaevis Carpenter 238 



Copied after Carpenter manuscript sketch. USNM. 



