237 Costa Rica Miocene— Olsson 65 



coarse on the anterior canal; the outer lip is heavil}^ thickened 

 by a large rib; anterior canal short and bent. 



Length 25, diameter S, last whorl 15 mm. 

 A single shell from Bocas, serves as tj^pe for this species. It 

 recalls the D. consors Sowerby, but differs in its much finer 

 sculpture. 



Gatun Sage: Bocas del Toro, Panaina. 



Driilia Citria, n. sp. Plate 5, figures 12, 13 



Shell small; whorls about 8, of which the first 2 belong to 

 the small, obtuse, smooth nucleus; the post-nuclear v/horls are 

 strongly sculptured with ribe and spirals; the upper 1-3 of the 

 spire-whorls carries a concave fascicle, bordered posteriorly by a 

 strong sutural cord to the ist post-nuclear whorl; the fasciole is 

 smooth or only faintly sculptured with fine spirals; the sculpture 

 consists on the last whorl of about 9 ribs which fade out rapidly 

 on the base and on the fasciole; the ribs are crossed on the earl}^ 

 spire-whorls by 2 spiral cords, becoming 3 on the later; on the 

 last whorl there are 12 more of which 6 are on the anterior ca- 

 nal; the intervals between the spirals, are 3 or more times as 

 wide as the spirals themselves and are sculptured with fine 

 spirals threads; aperture sub-elliptical, with a short and slightly 

 twisted anterior canal; anal sinus moderate. 



Height n, diameter 4 mm. 

 A small species, common in the coralline phase of the Gatun 

 at Port lyimon. 



Gatun Stage: Port Limon. 



Driilia aquanica, n. sp. Plate 5, figures 16, 17 



Shell small, slender with a long spire and a shorter last 

 whorl; whorls about 11, the nucleus composed of 2 small, smooth 

 convex whorls and about 9 post- nuclear; whorls strongly sculp- 

 tured with ribs and spiral cords; fasciole nearly 1-3 the width of 

 the spire-whorls, marked with fine spirals and bordered posteri- 



