PANAMIC-PACIFIC PELECYPODA 399 



flattened or depressed. The posterior side is pointed at the end and with a 

 narrow, excavated rostral area along its dorsal border. Hinge that of Eury- 

 tellina^ but more delicate; the right valve has two, small cardinal teeth, the 

 posterior one bifid, a small anterior lateral tooth is placed close to the 

 cardinals and a small, posterior lateral tooth is situated along the margin 

 just in front of the adductor scar; the left valve is provided with a small, 

 bifid, cardinal tooth with a socket on each side and also a small, partly 

 obsolete posterior cardinal lamina. The lateral teeth of the left valve are 

 formed by small, ridgelike laminae along the lower edge of the hinge plate, 

 the anterior one is much the longer. The pallial sinus is large and deep, its 

 end separated from the adductor scar by an open space, its lower limb 

 continuous with that of the pallial line. Surface sculpture produced by narrow 

 concentrics, neatly and finely crenulated by radial lines. 



This group of species is so well marked that T ellinidella deserves generic 

 status. Three species occur in the Panamic-Pacific region. 



1. Shell large (length 67 mm.), subsolid, the adductor scars impressed, the 

 hinge plate and teeth strong. Ventral margin straight in the midzone. 



T. princeps 



2. Shell smaller (length 62 mm.), thin, elliptical, the basal margin widely 

 rounded, the length less than twice the height, hinge weak. 



T. purpurea 



3. Shell thin, narrowly elliptical, its length more than twice the height, 

 hinge delicate, radial crenulations fine. 



T. mompichensis 



Tellinidella purpurea (Broderip and Sowerby) Plate 72, figure 2 



Tellinides purpurcus Broderip and Sowerby, 1829, Zool. Jour., vol. 4, No. 15, p. 363. — 



Sowerby, 1839, Zool. Beechey's Voyage, p. 153, pi. 42, fig. 2. 

 Tellina (Tellinides) purpurascens (Broderip and Sowerby), Hanley, 1846, Thes. Conch., 



vol. 1, Tellina, p. 295, No. 141, pi. 62, fig. 194 Real Leijos, Central America. 

 Tellina broderipii "Deshayes", Carpenter, 1855, Cat. Mazatlan Shells, Brit. Museum, 



p. 32. 

 Tellina {Tellinides) broderipii Deshayes, Maxwell Smith, 1944, Panamic Marine Shells, 



p. 64, fig. 851. 

 Tellina (Tellinidella) purpureas (Broderip and Sowerby), Hertlein and Strong, 1949, 



Zoologica, vol. 34, pt. 2, No. 9, pp. 80, 81. 



The shell is ovately elliptical, flattened to slightly convex, the umbones 

 near the middle. Color of surface is a rose-purple, usually darker on the 

 umbones and in the interior which is bright and glossy. The texture of the 

 valves is fairly thin. Surface sculpture formed by closely arranged, small 

 concentrics, much finer on the umbones, finely crenulated by radial lines. 

 The species is separted from the rarer T. princeps by it^ thinner and more 

 elliptical shell and much weaker hinge. 



Range — Gulf of California to northern Peru. Panama: Guanico; Burica 

 Peninsula. Ecuador: San Francisco; Sua; Punta Blanca; Point Ancon. Peru: 

 Tumbez; Punta Picos. 



Tellinidella princeps (Hanley) Plate 68. figure 3; 



Plate 72, figure 1 



Tellina princeps Hanley, 1844, Proc. Zool. Soc. London, p. 62 Tumbez.— Hanley, 1846, 

 Thes. Conch., vol. 1, Tellina, pp. 238, 239, pi. 63, fig. 206.— Sowerby, 1867, Conch. 

 Icon., vol. 17, Tellina, pi. 25, fig. 135.— Salisbury, 1934, Proc. Malacol. Soc. 

 London, vol. 21, pt. 2, p. 91, pi. 9, fig. 4 (figure of type). 



Larger and heavier than T. purpurea, the ventral margin nearly 

 straight in the mid-zone. Surface sculptured like that of T., purpurea. Color 

 dark rose-pink. 



