PANAMIC-PACIFIC PELECYPODA 225 



Shell small or of medium size, irregular, attached generally broadly by 

 the anterior side of the left valve. Surface of right valve is covered with 

 close-set, small spines. Usual color is a deep purple or coral-red, the large 

 hinge teeth always colored red. 



Range — Lower California to northern Peru and the Galapagos (in 

 part from Dall). Panama; Burica Peninsula. 



Chama frondosa Broderip Plate 34. figures 1-lb; 



Plate 86, figure 2 



Chama frondosa Broderip, 1835, Proc. Zool. Soc. London for 1834, p. 148. — Broderip, 

 1835, Trans. Zool. Soc. London, vol. 1, p. 302, pi. 38, figs. 1, 2.— Reeve, 1846, 

 Conch, Icon., vol. 4, Chama, sp. 1, pi. 1, figs, la Isla la Plata. — Hertlein and 

 Strong, 1946, Zoologica, vol. 31, pt. 3, No. 8, p. 109. 



The shell is generally large, coarse, subovate. Outer layer heavy, with 

 strong, concentric lamellae on the surface, generally extended into longi- 

 tudinally plaited foliations. Ground color usually a light purple or pink, the 

 finger-like foliations, a light yellow. Interior white, with a marginal band of 

 purple. 



Length 75 mm., height 91 mm., diameter (both valves) 76 mm. Manta, 

 Ecuador. 



This is the finest of the Pacific Coast Chamas but well-preserved speci- 

 mens are rare. 



Range — Gulf of California to Ecuador and the Galapagos (according 

 to authors). Ecuador: Manta; Isla la Plata. Panama Canal Zone: Venado 

 Beach. 



Chama pellueida Sowerby Plate 33, figures 2, 2a; 



Plate 34, figure 5 



Chama Pellueida Sowerby, 1835, Proc. Zool. Soc. London for 1834, p. 149. (Iquiqui). — 

 Broderip, 1835, Trans. Zool. Soc. London, vol. 1, p. 302, pi. 38, fig. 3. — Reeve, 

 1847, Conch. Icon., vol. 4, Chama, sp. 32, pi. 6, fig. 32. — Maxwell Smith, 1944, 

 Panamic Marine Shells, p. 56, figs. 708, 714. — Hertlein and Strong, 1946, 

 Zoologica, vol. 31, pt. 3, No. 8, p. 109. 



Shell generally rounded or subcircular, convex, wax}'- white, or coral- 

 red. Outer layer is thick, forming in the interior a wide, subtranslucent mar- 

 ginal band which contrasts sharply with the porcellaneous white of the in- 

 terior. Inner margin of shell minutely crenulated. Surface sculpture formed 

 by strong fluted spines and wavy, concentric lamellae. 



Range — Oregon to Chile. Peru: Bayovar, Yasila. Ecuador: Santa Elena. 



Genus PSEUDOCHAMA Odhner, 1917 

 Type species by subsequent designation, Gardner, 1926, Chama cristella 

 Lamarck. Recent, East Indies. 



Sinistral Chamas, the shell usually fixed by the right valve, its beaks 

 turned towards the right. Other characters as of the family. 



Pseudochama panamensls (Reeve) Plate 33, figures 1-lb 



Chama panamensis Reeve, 1847, Conch. Icon., vol. 4, Chama, sp. 45, pi. 8, fig. 45 

 Panama. , 



Shell generally ovate, higher (dorso-ventrally) than long (anter-pos- 

 teriorly), fairly large (68 to 70 mm.), solid, the right valve attached 



