PANAMIC-PACIFIC PELECYPODA 469 



The above description is based on a specimen of L. picta in the col- 

 lection of the Academy of Natural Sciences at Philadelphia purchased by- 

 Mr. T. B. Wilson from Sowerby about 1856 and is possibly a syntype. Its 

 locality is given as Peru but since Isla del Muerte in the Gulf of Guayaquil 

 is close to the Peruvian-Ecuadorian border, it could well be from the same 

 place. Both Sowerby and Hanley mention that the surface is painted with 

 wavy black lines which are not seen on the Academy's specimen which is 

 plain light brown in color. The specimen fits the figure of Conrad's L. 

 injlata in shape and size (described from Guayaquil) and is probably the 

 same species. (The type of L. injlata could not be located at the Academy.) 



Range — Ecuador and northern Peru. Ecuador: Isla del Muerte (Gulf 

 of Guayaquil). 



Family VERTICORDIIDAE 



Family with the characters as described below for the genus Verticordia, 



Genus VEllTICOKDIA Sowerby, 1844 

 Type species by monotypy, V. cardiiformis Sowerby. Pliocene ol 

 England. 



Shell generally small, suborbicular, cardiform, equivalve, the beaks 

 strongly prosogyrate above a deep, entering lunular indentation with 

 thickened margins. Shell texture heavy, nacreous within and with a thin, 

 chalky outer layer minutely shagreened. The hinge of the right valve shows 

 a stout, conical cardinal tooth placed behind the lunular indentation; there 

 are no laterals. Ligament internal, supported by a lithodesma. Pallial line 

 simple. Sculpture is formed by strong, radial ribs. 



Subgenus TRIGONULINA d'Orbigny, 1846 

 Type species by monotypy, T. ornata d'Orbigny. Recent, West Indies 

 and eastern Pacific, 



Shell similar to Verticordia, s.s. but with the posterior set of ribs more 

 widely spaced. Right valve with a long, posterior lateral socket. 



Verticordia (Trigonulina) ornata (d'Orbigny) 



Trigonulina ornata d'Orbigny, 1846, in de la Sagra, Histoire Physique, Politique et 



Naturelie de I'lle de Cuba; Mollusques, (Moll. Cubana), vol. 2, p. 291, pi. 27, 



figs. 30-33. 

 Verticordia ornata (d'Orbigny), Maxwell Smith, 1944, Panamic Marine Shells, p. 55, 



fig. 712. 

 Verticordia {Trigonulina) ornata (d'Orbigny), Hertlein and Strong, 1946, Zoologica, 



vol. 31, pt. 3, p. 102, pi. 1, fig. 7. 



Shell small, circular, with small prosogyrous beaks curved over the 

 deep, lunular indentation, brilliantly pearly within, and sculptured externally 

 with eight to ten large, curved, radial ribs which deeply indent the margin; 

 the set of seven anterior ribs are spaced evenly and fairly close together, 

 the others on the middle and posterior side unevenly, the two middle ribs 

 set as a pair bordered on each side by much wider spaces; these ribs may 

 be narrow and sharp, or more or less crudely beaded. Outer shell layer has a 

 fine granular texture, due to its composition and fine shagreening, generally 

 a cream-white color and contrast strongly with the shiny, nacreous luster 

 of the interior. 



Ma??imum length of shell a trifle over 5 mm. ; 



