1 66 Bulletin 39 338 



was collected from the coral limestones near Port L,imon, asso- 

 ciated with the common limonensis. 

 Gatun Stage; Port Linion. 



CLASS SCAPHOPODA 



Genus DEr^TALIUM Linnseus 



Subgenus DEMTALIUM, s. s. 

 DentalJum becasensis, n. sp. Plate 15, figures 2, 3 



Shell rather larger, solid, gently curved and increasing grad- 

 ually in size; the tip is more curved than the rest of the shell and 

 strongly hexagonal in cross- section; the sculpture consists at first 

 of 6 strong, primary ribs and wide, flat or slightl}^ concave in- 

 terspaces; the ribs are further increased b)^ the introduction of 6 

 intermediate ribs and still later b}' 12 more; these ribs are sub- 

 equal in size on the later portions of the shell; the interspaces are 

 finely transversely lined and faintly longitudinally striated. 

 I^ength 52, diameter 6.25 mm. 

 44, 4.75 mm. 



The Dentalhim bocasensis is fairly abundant in the shale 

 beds of Bocas Island. It is recognized hy its strongly hexagonal 

 tip and finely transversely lined interspaces, and strong longitudi- 

 nal sculpture. 



Gatun Stage: Bocas del Toro. 



Subgenus FISSI DENTALlUIVi Fischer 



DentaSium uscarianum, n. sp. Plate 15, figure i 



Shell large, solid and heavy; gently curved, and the taper of 

 the shell is slow and gradual; the tips are all broken on onr 

 specimens, but the later sections of the shell are circular or slight- 

 ly compressed dorsal-ventrally; the surface is sculptured with 

 about 24, low, subregular and roiuided longitudinal ribs with 



