PANAMIC-PACIFIC PELECYPODA 341 



as on the posterior surface, they form strong cross-threads. A lunular area 

 in front of the beaks of a narrow lenticular form is depressed and smooth. 

 Color of shell is white or pale straw-yellow, the beaks sometimes stained 

 with purple. Interior white or blotched with purple. 



Length 18.7 mm., height 13 mm., diameter 9 mm. Canoa, Ecuador. 

 Holotype, ANSP 218909. 



This appears to be a good species recognizable by its shape and sculp- 

 ture. It is abundant along parts of the Ecuadorian coast, all specimens are 

 strongly sculptured and of uniform size. 



Range — Panama south to Ecuador. Panama: Bucaro. Ecuador: Canoa. 



Donax naTiculns Hanley Plate 60, figures 3, 3a 



Donax navicula Hanley, 1845, Proc. Zool. Soc. London, pt. 13, p. 15 Gulf of Nicoya.— 

 Reeve, 1854, Conch. Icon., vol. 8, Donax, pi. 4, fig. 18.— Sowerby, 1866, Thes. 

 Conch., vol. 3, Donax, p. 314, No. 60, pi. 282, fig. 80.— Hertlein and Strong, 

 1949, Zoologica, vol. 34, pt. 4, p. 254, pi. 1, fig. 1. 



Shell generally small (length to about 25 mm.), elongate, slightly 

 convex and moderately solid. The beaks are placed at the posterior one- 

 third, the posterior-dorsal margin descending to a narrowly rounded end, 

 the posterior surface flattened to weakly depressed. The anterior side is 

 nearly twice the length of the posterior, rounded at its end, its ventral 

 margin showing a slight bulge. Surface smooth, porcellaneous, the fine 

 radials hardly visible, and no stronger radials are present on the posterior 

 surface. Color is mostly white, beneath a brown or straw-colored perio- 

 stracum, the posterior side and dorsal margins stained purple. Inner mar- 

 gins are finely crenulated. 



Range— G\i\{ of California to northern Peru. Mexican and Nicaraguan 

 records see Hertlein and Strong. Panama: Bucaro; Guanico; San Carlos; 

 El Lagartillo. Ecuador: Sua; San Francisco; Esmeraldas. Peru: Tumbez. 



Donax gracilis Hanley Plate 60, figure 5 



Donax gracilis Hanley, 1845, Proc. Zool. Soc. London, pt. 13, p. 15 Gulf of Guayaquil. 

 —Reeve, 1854, Conch. Icon., vol. 8, Donax. pi. 6, fig. 38.— Sowerby, 1866, Thes. 

 Conch., Donax, p. 314, No. 59, pi. 282, figs. 76-79.— Hertlein and Strong, 1949, 

 Zoologica, vol. 34, pt. 4, pp. 253, 254, pi. 1, figs. 4, 6. 



Shell small (length from 20 to 27 mm.), narrowly elongated, the beaks 

 placed between the posterior one-third and one-fourth. Posterior end short, 

 attenuated, the anterior side higher and more widely rounded at the end. 

 Surface smooth, porcellaneous, the radials showing indistinctly. Color white 

 to brown, sometimes rayed. 



Related to D. californicus Conrad of California but longer and nar- 

 rower, more compressed and the posterior end is more acutely pomted. 



Range— GuU of California to northern Peru. Nicaragua: Corinto (H. 

 and S.) Panama: Bucaro; Puerto Mensabi; El Lagartillo. Columbia: Isla 

 del Gallo. Ecuador: Santa Elena. Peru: Tumbez; Zorritos; Lobitos; 

 Negritos. 

 Donax pnnctatostriatus Hanley Plate 61, figures 6-6b 



Donax tunctato-striata Hanley, 1843, Proc. Zool. Soc. London, pt. 11, p. 5. Hab. - - -.> 

 —Hanley, 1843, Cat. Rec. Bivalve Shells, p. 84, pi. 14, f.g. 24 {&% Junctato- 

 striatus in plate explanation).— Reeve, 1854, Conch. Icon., vol. 8, Donax, pi. 

 3, figs. 16a, 16b. 



