247 



Costa Rico Miocene — Olsson 



75 



Height 10.75, diameter 3.25 mm. 



The Drillia lithocolleta Watson is a recent deep-water 

 species, dredged by the Challenger and the Blake, at several 

 stations in the West Indies and off the Florida coast, from depths 

 of 400 to nearly 1000 fathoms. The Bocas shell seems to be 

 ver}^ closely related to the recent species; differing only from 

 Ball's figure in the Blake Report (plate 11, fig. 61), in being 

 somewhat more slender, with heavier tubercles and a longer base. 



Gatu7i Stage: Bocas del Toro, 



Drillia cocoslna, n, sp. Plate 5, figure 14 



Shell small, glassy or translucent in texture; spire twice or 

 more the length of the last whorl and the canal; whorls 8 plus, 

 the earlier ones missing; no anal fasciole; the sculpture consists 

 at first of a lower row of small tubercles, but a second or upper 

 row soon begins to appear and on the last whorl, this upper set 

 of tubercles is very nearly equal to the lower; the last whorl has 

 about 13 of these tubercles, in addition the whorl is finely sculp- 

 tured with fine, regular, closely spaced spiral threads which cov- 

 er the entire whorl and the canal, but lea,ving the tops of the 

 tubercles smooth; aperture ovate, with a short, twisted canal. 

 Length 12, diameter 3.5 mm. 



This interesting species from the shales near the city of 

 Bocas del Toro, is related to the recent Drillia oleacina Ball 

 dredged from rather deep water in the Gulf of Mexico and else- 

 where in the West Indies. In differs from that species in being 

 less slender and with a larger body-whorl. 



Gahin Sage: Bocas del Toro. 



