PANAMIC-PACIFIC PELECYPODA 397 



ductor extending to the beaks and the adductor scars are often deeply im- 

 pressed. Color white or rose, generally more or less banded, the beaks colored 

 more deeply. The surface sculpture is formed by neat, even, concentric rib- 

 bons (about 5 to each 2 mm.), which begin at the rostral angle and cover 

 the whole disk rather uniformly. The rostral area is narrow, flattened or 

 excavated, and with simpler sculpture. There is usually a small sulcus along 

 the anterior-dorsal margin. 



Length 44 mm., height 26.6 mm., diameter 11.2 mm. Guanico, Panama. 



This is a small or medium-sized species characterized by its rather heavy 

 shell, white or pink color, the shades of color often arranged in wide, con- 

 centric bands, the umbones shaded generally a deep rose-red. The surface 

 is neatly marked with strong, uniform, concentric ribbons. The species 

 appears to be common and widely distributed. 



There is some doubt whether E. simtdans should be considered as fully 

 distinct from the Caribbean eurytellinid, commonly identified as E. punicea, 

 especially as the locality for Born's specimens was not stated in its de- 

 scription. In general, E. simulans is smaller and somewhat longer, and also 

 usually of a lighter color, than the Caribbean form. 



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

 Guanico. Panama Canal Zone: Venado Beach. Ecuador: Point Ancon; 

 Mompiche; Galeras Peninsula; Santa Elena. Peru: Tumbez. 



Enrytellina (Eurjtellina) mantaensis (Pilsbry and Olsson) 



Tellina {Eurytellina) mantaensis Pilsbry and Olsson, 1943, Nautilus, vol. 56, No. 3, p. 

 80, pi. 8, figs. 1-4.— Hertlein and Strong, 1949, Zoologica, vol. 34, pt. 2, No. 9, 

 pp. 75, 76. 



The shell is small (length generally less than 34 mm.), rose-colored, 

 stained more deeply so on the umbones and often somewhat brownish 

 ventrally; the different shades of color sometimes arranged in concentric 

 bands. General sculpture consists of flat, concentric ridges which are well 

 developed below the middle of the disk and around the anterior end but the 

 umbones and the middle zone of the disk is smooth. The right valve has the 

 posterior-dorsal area marked off well and more heavily sculptured with 

 regular, waved, raised threads; in the left valve, the posterior-dorsal area 

 is nearly smooth. A thickened ray borders the inner side of the anterior 

 adductor scar. Pallial sinus deep, confluent below, its rounded end nearly 

 reaching to the anterior adductor scar. 



Length 31 mm., height 17 mm., diameter 6.75 mm. 



The smallest of the Panamic-Pacific Eurytellinas. 



Rang — Panama to Ecuador. Panama: Gulf of Chiriqui (Hertlein and 

 Strong); Pedro Gonzales Island (Pearl Islands), USNM 589750. Ecuador: 

 Manta. 



Eurytellina (Eurytellina) prora (Hanley) Plate 71, figures 6, 6a 



Tellina prora Hanley, 1844, Proc. Zool. Soc. London, p. 61 Santa Elena. — Hanley, 1846, 

 Thes. Conch., vol. 1, Tellina, p. 243, No. 39, pi. 60, fig. 152.— Sowerby, 1866, 

 Conch. Icon., vol. 17, Tellina, pi. 18, fig. 90.— Maxwell Smith, 1944, Panamic 

 Marine Shells, p. 65, figs. 827, 840. 



Tellina {Eurytellina) prora Hanley, Hertlein and Strong, 1949, Zoologica, vol. 34, pt. 

 2, No. 9, pp. 77, 78. 



Shell elliptical-trigonal, nearly equilateral, the beaks submedian, sub- 

 solid and of low convexity. Shell white or pale rose-pink, the white and pink 



