PANAMIC-PACIFIC PELECYPODA 289 



Garachine; Panama City; Rey Island, Pearl Islands; Puerto Chame. 

 Panama Canal Zone; Amador Beach; Balboa; Palo Seco. Colombia: Buena- 

 ventura; Isla del Gallo. Ecuador: Puno Island. Peru: Tumbez. 



Lamelliconcha unicolor (Sowerby) Plate 40, figure 3; 



Plate 49, figures 4, 4a 



Cytherea unicolor Sowerby, 1835, Proc. Zool. Soc. London, p. 23 Real Llejos. — Sowerby, 



1851, Tiies. Conch., vol. 2, p. 629, pi. 131, figs. 90, 91 (as Cytheraea). 

 Cytherea ligula Anton, 1839, Verzeichniss der Conchyl., p. 7 no locality cited. — Philippi, 



1844, Abbild. und Beschreib. Conchylien, bd. 1, heft. 6, Cytherea, p. 149, pi. 1, 



fig. 2. 

 Dione unicolor (Sowerby), Reeve, 1863, Conch. Icon., vol. 14, Dione, pi. 8, figs. 33a, 33b. 

 Pitar {Pitar) unicolor (Sowerby), Hertlein and Strong, 1948, Zoologica, vol. 3, pt. 4, 



No. 13, p. 171. 



Shell ovate, solid and heavy, slightly convex, the beaks placed near the 

 anterior one-third, curved over a small, depressed, cordate lunule, the color 

 a uniform white or vinaceous brown, the surface glossy. Sculpture is formed 

 by low, rounded, concentric lamellae, uniform and strong on the umbones, 

 the anterior submargins and along the posterior-umbonal angle, usually 

 fading out across the middle of the disk. Faint radial striae are visible on 

 some specimens. Posterior-umbonal slope is more or less angled, the surface 

 above it slightly flattened or weakly rounded. Interior white, often clouded 

 with vinaceous, the pallial sinus long and deep. 



Length 54 mm., height 46.5 mm., diameter 26.8 mm. Guanico. 



Range — Gulf of California to Ecuador. Panama: Biicaro; Guanico. 

 Colombia: Buenaventura. Ecuador: Atacames; Sua; Jipijapi (Sowerby). 



Lamelliconcha callicomata (Dall) Plate 40. figure 4; 



Plate 49, figure 6 



Pitaria {Lamelliconcha) callicomata Dall, 1902, Proc. U. S. Nat. Museum, vol. 26, No. 



1312, pp. 389, 402, pi. 16, fig. 8 (Bay of Panama). 

 Pitar callicomata Dall, Strong, Hanna and Hertlein, 1933, Proc. California Acad. Sci., 



ser. 4, vol. 21, No. 10, p. 118 Acapuico, Mexico. 

 Pitar {Lamelliconcha) callicomatus Dall, Hertlein and Strong, 1948, Zoologica, vol. 33, 



pt. 4, p. 175. — Hertlein and Strong, 1955, Bull. Amer. Mus. Nat. Hist., vol. 107, 



art. 2, pp. 191, 192. 



Shell large or medium-sized, elongated ovate, moderately convex, 

 white, rather earthy and covered with sharp, thin, concentric lamellar rib- 

 lets, every third or fourth of which is larger and higher than the others; 

 they are also somewhat higher along the anterior-umbonal slope. The pri- 

 mary riblets are widely spaced and generally show one or more, smaller, 

 secondaries between them as well as still smaller tertiary threads between 

 the latter. Lunule small, cordate, and nearly smooth. Interior pure white, 

 the pallial sinus long, linguiform, its upper limb nearly horizontal. Internal 

 margin of valves smooth. 



Length 47.6 mm., height 36.7 mm., diameter 24.3 mm. 



A distinctive species, often obtained by the shrimp fishermen. 



Range — Coast of Mexico to Panama. Panama: Panama Bay in 14 

 fathoms of water (Dall, USNM); Bay of Panama (shrimpers, H. A. John- 

 son coll.); Gulf of Chiriqui (in 35-40 fathoms, Hertlein and Strong). 



