PANAMIC-PACIFIC PELECYPODA 6S 



XucQlana (Saccella) dranga, new species Plate 2, figure 5 



Shell of medium size (length about 12 mm.), subelliptical, the length 

 about twice the height, the beak and umbone placed nearly in the middle. 

 There is a deeply indented ray along the lower side of the posterior or 

 rostral keel which sharply bends or in some cases slightly dislocates the 

 sculptural lamellae which cross it; the anterior ray is much weaker or wholly 

 absent, the lines of sculpture being merely depressed, or weakly flexed by 

 it. The posterior end is pointed, occasionally with a smaller point below it 

 on the lower side of the indented ray. Sculpture is strong and on most 

 specimens quite uniform; it is formed by strong, triangular, concentric 

 lamellae or riblets, their dorsal side a trifle shorter and steeper, sometimes 

 with a small overhang between deeply grooved or wavelike interspaces of the 

 same width. The concentrics are generally of uniform size across the 

 middle of the disk (20 or more), a little smaller on the surface of the um- 

 bone and somewhat more crowded together near the ventral margin; an 

 occasional one is deeper and marks a rest period. The rostrum is large, set 

 apart by the posterior or rostral angle, which is nodose or serrated by the 

 concentrics; its shape is narrowly elliptical and marked with fine, parallel 

 lamellae. The lunule is small and narrow, flat, with cross sculpture formed 

 by the roots of the hinge teeth. Hinge provided with strong teeth, in an 

 equal series, about 18 teeth in the anterior row and about 16 in the posterior 

 row, the middle ones extremely small. 



Length 12 mm.; height 6 mm.; diameter 2.3 mm. 



Esmeraldas, Ecuador. Holotype ANSP 218926. 



This may be a widely distributed species, often identified with N. 

 elenensis (Sowerby) from which it is separated by its greater length in ratio 

 to its height and sharper sculpture. Relations are also indicated with N. 

 acapulcensis Pilsbry and Lowe. 



The species is named for the late Mr. Ted Dranga, well-known shell 

 collector and who acco^mpanied the author on his Ecuadorian expedition 

 of 1955. 



Range — Off Ecuador but probably north to Mexico. Ecuador: 

 Esmeraldas. 



Nncalana (Saccella) elenensis (Sowerby) Plate 1, figure 9 



Nucula elenensis Sowerby, 1833, Proc. Zool. Soc. London for 1832, p. 198. — Sowerby, 1833, 

 Conch. Illust., Nuculae, p. 4, No. 19, pi. 15, fig. 1+ "Tumbez". 



Leda elenensis Hanley, in Sowerby, 1860, Thes. Conch., Nuculidae, p. 121, No. 29, figs. 

 70-72. (Fig. 70 is considered as the typical form). 



Nuculana (Saccella) elenensis (Sowerby), Hertlein and Strong, 1940, Zoologica, vol. 

 25, pt. 4, pp. 393, pi. 1, figs. 17, 18, 19 (copied from Hanley) ; the others are 

 N. acapulcensis Pilsbry and Lowe. Not A'^. elenensis Maxwell Smith, 1944, 

 Panamic Marine Shells, fig. 626B. 



The shell is small or medium-sized (length 12-13 mm.), short, stubby, 

 soHd and convex, with nearly central beaks, rounded anterior side and a 

 narrowed, pointed posterior end, deeply concave on the dorsal margin. The 

 sculpture is formed by subequal, coarse, concentric riblets between deeply 

 grooved, sometimes pitted interspaces. There is usually an impressed zone 

 extending from the beak to a point near the anterior-ventral margin causing 

 a slight flattening or flexing of the concentric riblets. On the posterior side, 

 there is a wider and more deeply impressed ray just below the keel which 



