4^7 Costa Rica Miocene — Olsson 255 



also found as a Miocene fossil in the Bowden beds of Jamaica 

 and in Santo Domingo. 



GatiDi Stage: Middle creek. 



Strigilla musanica, n. sp. Plate 26, figure 18 



Shell subtrigonal, moderately convex, subequilateral; the 

 umbos are broad and wide, situated about the middle of the shell, 

 with the greatest convexity of the shell lying along the anterior- 

 umbonal slope; the anterior end is broad and rounded, the pos- 

 terior slightly narrow, but not produced; the sculpture is divid- 

 ed between three areas, the posterior, central and anterior, each 

 of which is set off from the adjacent one, by a marked change in 

 sculpture along a well-defined line; on the anterior area, it con- 

 sists of a concentric series of wave-like incised lines, the crest of 

 the wave lying near the posterior side and directed as usual dor- 

 sally; on the central area, the lines are vertically directed, com- 

 mencing on the lines bordering the posterior side; on the poster- 

 ior area, the lines commence on the anterior side and pass verti- 

 call}', forming therefore with the middle lines very acute an- 

 gles; the interior is concealed in our specimen. 



Length 13.00, height 11.50, diameter of the right valve 

 3.00 mm. 



Differs from Strigilla carnaria Linne of the recent West In- 

 dian fauna, by being more inequilateral, more convex and in de- 

 tails of its sculpture which is sharply divided between three areas 

 as described. The interior of the type specimen is concealed, so 

 that the features of the pallial line and sinus cannot be deter- 

 mined. 



Gatun Stage: Hill No. j. Banana River. 



Genus METIS, H. and A. Adams 

 Metis barba, n. sp. Plate 29, figures 3, 4 



Shell subquadrate, inequilateral, with the beaks situated at 

 the anterior two-thirds of the total length of the shell; anterior 



