404 AXEL A. OLSSON 



Anterior side nearly twice the length of the posterior, high, its dorsal and 

 ventral margins subparallel, end widely rounded. The posterior area is 

 short, uniformly flat, or slightly convex, sloping from the umbonal angle 

 downward to its margin which is broadly arcuate, its end blunt. Shell is 

 thin or subsolid, the adductor scars frequently showing as sunken areas. 

 Surface smoothish but under a lens the sculpture is seen to be formed by 

 even, narrow, concentric bands between sharply incised lines which ap- 

 parently overrun the much finer, indistinct growth incrementals. Pallial 

 sinus is deep, extending nearly to the anterior adductor, confluent with 

 the pallial line for most of its length. 



Length 10 mm., height 8.6 mm., diameter 3.3 mm. 



This small species is easily recognized by its bright, rose-red color. It 

 is fairly common at Panama. 



Range — Mexico to northern Peru. Mexico: Guaymas. Costa Rica: Gulf 

 of Nicoya. Panama: Panama City; Bella Vista. Panama Canal Zone: Fort 

 Amador; Venado Beach. Colombia: Isla del Gallo. Peru: Zorritos. 



Moerella (Moerella) cerrosiana (Dall) 



Tellina {Angulus) cerrosiana Dall, 1900, Proc. U. S. Nat. Museum, vol. 23, No. 1210, 

 pp. 303, pi. 3, fig. 11. "Off Cerros Island, Lower California in 9-10 fathoms." — 

 Keen, 1958, Sea Shells of Tropical West America, p. 170, fig. 39+. 



The shell is small (length about 6.5 mm.), broadly elongate, slightly 

 flexed, thin, glassy, the anterior side nearly twice the length of the posterior 

 and widely rounded at its end. The left valve is slightly convex for the 

 most part; the right valve is of similar inflation except that it is slightly 

 impressed across the middle due to a weak flexing of the end towards the 

 right. The surface color is white, often glassy, and marked with fine, con- 

 centric lines forming narrow ribbons; in addition there is often visible fine 

 radial streaks or even a pattern of divaricating branches. The hinge is 

 normal for the genus; the left valve has a single, bifid, cardinal tooth, and 

 the laterals are weak or absent; the right, anterior lateral tooth is long and 

 strong. Because of the thin texture of the shell, the pallial sinus is usually 

 indistinct but when visible, it is seen to be large with a high angle under 

 the beak and almost reaching to the anterior adductor scar, its lower 

 line joined with the pallial Hne. 



This is a small species. Specimens were dredged in some numbers at 

 Manta and at Esmeraldas; these Ecuadorian specimens seem to have the 

 posterior end a little longer than shown for the typical form but otherwise 

 are identical. 



Range — Lower California to Ecuador. Ecuador: Manta; Esmeraldas. 



Sloerella (Moerella) hiberna (Hanley) Plate 84, f:gure 6 



Tellina hiberna Hanley, 1844, Proc. Zool. Soc. London, p. 149. — Hanley, 1846, Thes. 

 Conch., vol. 1, Tellina, p. 282, No. 112, pi. 57, fig. S3 Panama, Gulf of Guaya- 

 quil. — Salisbury, 1934, Proc. Malacol. Soc. London, vol. 21, pt. 2, p. 91, pi. 

 13, figs. 7, 8, 9. 



Tellina [Angulus) panamensis Dall, 1900, Proc. U. S. Nat. Museum, vol. 23, No. 1210, 

 p. 319, pi. 3, fig. 3 Panama. (Not T. panamensis Philippi, 1848.) 



Tellina {Angulus) panamensis Dall, 1900, Proc. U. S. Nat. Museum, vol. 23, No. 1210, 

 p. 319, pi. 3, fig. 3 Panama. (Not T. panamensis Philippi, 1848.) 



Tellina tabogensis Salisbury, 1934, Proc. Malacol. Soc. London, vol. 21, pt. 2, p. 86. (New 

 name for T. panamensis Dall.) 



Tellina (Moerella) tabogensis Salisbury, Hertlein and Strong, 1949, Zoologica, vol. 34, 

 pt. 2, pp. 72. 73. 



