64 AXEL A, OLSSON 



may deeply emarginate the posterior-ventral end so that it appears double 

 pointed. There is a small, narrowly linear lunule and a much larger, well-, 

 sculptured rostrum covering the whole length of the posterior area between 

 the dorsal margin and the keel. 



This species is variable and several subspecies or races could easily be 

 recognized. The typical form of N. elenensis is shown by figure 14 in Sower- 

 by's Conchological Illustrations and by Hanley's figure 70 in his monograph 

 of the Nuculidae. To this shell, Hanley proposed the varietal name of 

 gibbosa and described it as follows: 



Beaked-ovate, very ventricose, the anterior indented ray not very 

 conspicuous; ribs scarcely so broad as their intervals; front extremity only 

 slightly narrowed; rostrum much recurved, its tip above the middle; ventral 

 margin remarkably arched in front, and much rising behind. 



This species is relatively rare at most localities, generally small and 

 seldom exceeding 12 mm. in length. Although variable in its convexity, the 

 species is easily distinguished by its rather stubby form, strong sculpture 

 and by its well-marked posterior rib so that the posterior end appears as 

 if double pointed. The anterior ray is weak or strong, and it often forms a 

 slight flexure across the anterior slope. 



Range — Coast of northern Peru and Ecuador. Ecuador: Esmeraldas; 

 Manta; Santa Elena; Ancon. Peru: Bay of Sechura. 



^'ucnlana (Saccella) elenensis crispa (Hinds) 



Nucula crispa Hinds, 1843, Proc. Zool. Soc. London, p. 100 (Hab. Gulf of Nicoya; from 

 36 fm.— Hinds, 1844, Zool. Voy. Sulphur, Moll. pt. 3, p. 64, pi. 18, fig. 14. 



Leda crispa (Hinds), Hanley, 1860, in Sowerby, Thes. Conch., vol. 3, Nuculidae, p. 134, 

 sp. 50, pi. 229, figs. 107, 108. 



Nuculana crispa (Hinds), Hertlein and Strong, 1940, Zoologica, vol. 25, pt. 4, p. 403. 



Shell small, (length about 6.5 mm.), stubby, coarsely concentrically 

 costellated throughout, the riblets somewhat shelving and about as broad 

 as their intervals which are radiatingly lirated at the posterior end. The 

 posterior end is sharply rostrate, bordered by a deeply indented ray below, 

 the rostrum large, with close concentric lines bordered by a coarsely 

 costellated keel. 



This form was described as a species by Hinds. It is here considered 

 as a subspecies of N. elenensis in which the anterior indented ray is strongly 

 developed. 



Range — Panama southward to Ecuador. 



Ifncnlana (Saccella) callimene (Dall) Plate 1, figures 7, 7a, 7b 



Leda (Jupiteria) callimene Dall, 1908, Bull. Mus. Comp. Zool., vol. 43, No. 6, p. 372, 



pi. 17, figs. 3, 4 "Gulf of Panama, 259 fathoms". 

 Nuculana (Saccella) callimene (Dall), Hertlein and Strong, 1940, Zoologica, vol. 25, pt. 



4, p. 393, pi. 1, fig. 13. 



Shell small (average length, 15 to 16 mm.), solid, plump, white or 

 yellowish brown, equivalve and inequilateral. No escutcheon but the pos- 

 terior-dorsal area is wide, bounded by a rostral angle; there is an elongated, 

 narrow lunule poorly defined by a slight change of sculpture. Sculpture con- 

 sists of numerous, small, concentric riblets between somewhat wider, grooved 

 interspaces, uniformly developed over the whole surface except for a narrow, 



