PANAMIC-PACIFIC PELECYPODA 271 



Range — Mexico to northern Peru. Panama: Puerto Mensabi; Bucaro. 

 Panama Canal Zone: Balboa. Colombia; Buenaventura; Isla del Gallo. 

 Ecuador: Limones; Mompiche; Palmar, near Santa Elena, Peru: Tumbez. 



Genus GOULDIA C. B. Adams. 1847 

 {Thetis C. B. Adams, 1845, not of Sowerby, 1826). 

 Type species by subsequent designation, Dall, 1883, Gonldia cenna 

 (C. B. Adams). Recent, Florida and the West Indies. 



Shell small, subcircular to subtrigonal with a small, inconspicuous, 

 often flattened umbone ending in a pointed or slightly prosogyrate beak. 

 Hinge with three cardinal teeth in each valve of which the central tooth 

 in the right valve is large, the central tooth in the left valve similar but 

 bifid; an anterior lateral tooth is found in each valve. Adductor scars plain, 

 nearly equal in size. Pallial sinus shallow. Lunule large and bounded by 

 an incised line. The surface is sculptured by small radial and concentric 

 riblets, the concentrics generally strongest in the middle and the radials on 

 the sides, often together producing a cancellate pattern. 



Gouldia C. B. Adams, 1847 is a substitute name for Thetis C, B. Adams, 

 1845 preoccupied by Sowerby, 1826. The original Thetis was proposed for 

 two species, cerina and parva, the first a venerid, the other a crassitellid. 

 In the subsequent works of the author, and of Carpenter, and H. and A. 

 Adams, the genus Gouldia was used mainly for shells now referred to 

 Crassinella of Guppy. Dall's selection of G. cerina as type species, fixed 

 the genus Gouldia as a member of the Veneridae. 



Gonldia ealifornica Dall Plate 39, figure 9 



Gouldia ealifornica Dall, 1917, Proc. U.S. Nat. Museum, vol. 51, No. 2166, p. 579 Gulf 

 of California near La Paz. — Hertlein and Strong, 1948, Zoologica, vol. 33, 

 pt. 4, No. 13, p. 168. 



Gafrarium {Gouldia) stephensae E. K. Jordan, 1936, Contr. Dept. Geol. Stanford 

 University, vol. 1, No. 4, p. 136, pi. 19, figs. 10, 11. 



Shell small, subcircular to ovate-triangular, thin, white, with touches 

 of brown along the dorsal border. The anterior lateral tooth is large and 

 prominent, the pallial sinus small. Sculpture reticulate, the concentric ele- 

 ments more prominent in the middle of the disk, the radial towards the 

 end of the valves. Inner valve margins smooth. 



Length 6 mm., height 5.5 mm., diameter 3 mm. (Dall), 

 Length 5.5 mm., height 4.75 mm., diameter 2.8 mm, Esmeraldas, 

 Ecuador. 



Similar to G. cerina of West Indian waters but smaller and with coarser 

 sculpture, more strongly reticulated over the whole disk. Some specimens 

 from Manta have a purplish color; others are white. 



Range — Gulf of California south to Ecuador. Ecuador: Esmeraldas; 

 Manta; Santa Elena. 



Subfamily Pitarlnae Stewart, 1930 



The surface of the shell is smooth, plain or with strong, concentric 

 sculpture, never radially ribbed, the inner side of the ventral margin smooth 



