390 AXEL A. OLSSON 



Subgenus PISOSTRIGILLA, new subgenus 



Type species Strigilla pisiformis (Linne). Caribbean. 



Shell generally small, convex, solid, with a coarse hinge. Sculpture of 

 oblique lines or sulci as in Strigilla, s.s. but with a line of sharp flexure or 

 zigzag bends along the middle of the posterior-dorsal area, 



Strigilla (Pisostrigilla) panamensis, new species Plate 39, figures 8-8b 



Shell small (length 6 to 8 mm.), solid, strongly convex, subcircular, 

 the posterior side nearly as rounded as the anterior and only slightly longer. 

 Umbones wide, the small beaks inconspicuous and closely appressed to the 

 hinge margin. Sculpture uniformly strong over the whole surface with the 

 principal line of divarication along the posterior slope straight and sharp, 

 the anterior one much weaker, showing as a wide, shallow bend, convex 

 upward, with or without a smooth tract along it; on the middle zone of 

 the disk, the sulci are inclined obliquely to the ventral margin forming 

 angles between 60 and 70 degrees. On the posterior-dorsal area a line of 

 zigzag flexure lies along the middle. Color white in all the specimens 

 examined. 



Length 6.6 mm., height 6.1 mm., diameter 2 mm. (a left valve), 

 Guanico, Panama. Holotype, ANSP 218938. Paratype, length 7.7 mm., 

 height 7.5 mm., diameter 2.8 mm. (a right valve) Guanico. 



This is a small, plump species similar to S. pisiformis of the Caribbean 

 but has a more rounded form and a pure white color. 



Range — Panama to Ecuador. Panama: Guanico. Colombia: Isla del 

 Gallo. Ecuador: Punta Blanca; Santa Elena. 



Subgenus SEffPLISTRIGILLA, new subgenus 



Type species Strigilla strata, new species. 



Shell small, subovate, convex, the surface marked with strongly oblique 

 incised lines or sulci crossing the shell from one margin to the other but 

 without any line of flexure or a change in direction. 



Strigilla (Slmpllstrig.lla) strata, new species Plate 39, figure 7 



The shell is small, rounded, subovate, white, relatively solid in texture 

 and moderately convex. The umbones are submedian, the beaks at the end 

 bluntly trigonal. The nepionic surface of the umbone is relatively large and 

 sculptured with hairlike concentrics; this type of sculpture ends sharply 

 and on the succeeding adult portion, the sculpture is produced by rather 

 wide, inclined bands set apart between sharply incised lines which run 

 obliquely across the face of the disk from the posterior or ventral margins 

 to the anterior-dorsal side, the result a rather coarse pattern; these bands 

 are continuous and show little or no flexing or any change of direction along 

 the posterior and anterior submargins. 



Length 7.2 mm., height 6.8 mm., semidiameter 3.1 mm. (a left valve). 

 Punta Blanca, Ecuador. Holotype, ANSP 218950. 



A rare and unusual species easily known by its sculpture. 

 Range — Panama southward to Ecuador. Panama: El Lagartillo. 

 Ecuador: Punta Blanca. 



Genus EURYTELLDfA Fischer, 1887 

 Type species by original designation, Tellina punicea Born. 



