PANAMIC-PACIFIC PELECYPODA 317 



Subgenus NARANIO Gray, 1853 



Type species by subsequent designation, Dall, 1900, Naranio costata 

 (Lamarck) {^Venus lapicida Gmelin). 



Shell generally ovate to oblong, plump. Sculpture of radial riblets often 

 divaricated or with sharp, zigzag bends. 



Petricola (Xaranio) botula, new species Plate 55, figures 7, 7a, 8 



The shell is relatively small (length about 15 mm.), broadly to nar- 

 rowly elongate, equivalve, convex, white or cream-colored. The umbone 

 and beak is placed near the anterior one-fourth, the anterior end short 

 and well-rounded. The shell is highest and most convex along a line running 

 from the beak downward; behind this slope, the surface over the middle 

 portion of the disk is slightly impressed. The posterior-umbonal slope is 

 rounded to weakly angled, the dorsal surface above it somewhat flattened. 

 Surface is finely marked with small radial threads, simple in the middle 

 of the umbonal disk and on the anterior slope but towards the ventral 

 margin and the ends, the markings are irregularly divaricate; there is also 

 a line of marked divarication along the posterior-umbonal slope and at 

 the anterior one-fourth. The hinge is typical, the area of the ligament 

 short and excavated. The pallial sinus is large, rounded, and extends to 

 about the middle of the shell cavity, the adductor scars distinct, the an- 

 terior one is much larger than the other. 



Length 14.3 mm., height 7.9 mm., diameter 6.7 mm. Holotype, ANSP 

 218908. 



Length 13.7 mm., height 8 mm., diameter 6.7 mm. 



Length 15.5 mm., height 8.5 mm., diameter 8 mm. 



A rock borer, the shell varying somewhat in shape, some specimens 

 being short and stubby, others narrow and elongate. Found boring into 

 Tertiary rocks at Guanico. 



Range — Panama. Panama: Guanico. 



Petricola (Naranio) charapota, new species Plate 54, figure 7 



Shell of medium size, subrectangular, subsolid, and of a brown-red 

 color, the beak strongly anterior in position, the posterior side hence much 

 longer, inflated, or strongly convex along the zone of the umbonal slope 

 extending from the beak to the posterior-ventral corner. Dorsal and ventral 

 sides are nearly parallel, the posterior end itself rounded, the anterior side 

 short and subtruncate. Sculpture is formed by fine to medium size, radial 

 riblets which are uniformly distributed over the whole surface except 

 along two lines, the one extending along the middle of the posterior um- 

 bonal slope, the other at the anterior one-third at which place some of the 

 riblets split, bend, or become hook-shaped. Color is a faded, reddish brown 

 in the type specimen, similar over the whole valve. Pallial sinus is large, 

 rounded, extending to about the middle of the shell cavity. Adductor scars 

 large, the posterior one placed high. Ligament area deeply excavated and 

 short. 



Length 30 mm., height 20.2 mm., diameter 10 mm. a left valve. 



Holotype, ANSP 218907. 



Range — G)ast of Ecuador. Ecuador: Charapota. 



