i66 



Bulletin 39 



338 



was collected from the coral limestones near Port Limon, asso- 

 ciated with the common limonensis. 

 Gatun Stage; Port Limon. 



CLASS SCAPHOPODA 



Genus DENTAL I UIVI Unnseus 



Subgenus DENTAL SUM, s. s. 

 DentaEium bocasensts, 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, primar}^ ribs and wide, flat or slightly concave in- 

 terspaces; the ribs are further increased by the introduction of 6 

 intermediate ribs and still later by 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. 

 Length 52, diameter 6.25 mm. 



44, 4.75 mm. 



The Dentaliurii bocascmsis is fairly abundant in the shale 

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

 tip and finely transversely lined interspaces, and strong longitudi- 

 nal sculpture. 



Gatun Stage: Bocas del Toro. 



Subgenus FtSS I DENTALmR/S Fischer 



Dentalium usoarianum, 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 our 

 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 rounded longitudinal ribs with 



