315 



Costa Rica Miocene — Olsson 



143 



Uscari Stage: Sapote, C. R. {Gabb) 

 Gatun Stage: Banana River. 



Zone E, Saury Creek. 



Zoni 5, East Grape Point Creik. 



Genus CREPITACELLA Guppy 

 CrepitaceIJa limonensls, n. sp. Plate 15, figure 17 



Shell small, melanoid in form, with a large body-whorl and 

 shorter conic spire; nucleus of 2 small, smooth whorls followed 

 by 5 post-nuclear whorls; sutures distinct; the whorls are slight- 

 ly coronated and crossed by oblique and slightly curved ribiets 

 which become headed on the coronate edge of the spire-whorls 

 just below the upper sutures; on the last whorl, the ribs do not 

 pass below the middle; the surface is covered with faint spiral 

 threads, most distinct on the base of the body- whorl; aperture 

 elliptical, with a thin, oblique outer lip and a subobsolete anteri- 

 or canal; pillar straight. 



Height 8, diameter 4.5, aperture 4 mm. 



The Costa Rican shell, although possibly not mature, is much 

 smaller than the C. cepula Guppy from the Miocene of Venezuela 

 and Santo Domingo of the same number of ribs. It differs also 

 in having but 2 nuclear whorls, while cepula has 3. The corona- 

 tion of the whorls which is such a striking feature of the Domin- 

 ican shell, is very much less and inconcpicuous. The longitud- 

 inal costse are more numerous and produce a fine circle of beads 

 as they cross the small coronate edge of the spire-whorls. 



Gatun Stage: Port Liinon, 



Boras del Toro. 



Genus CERITHfUM Adanson 



Cerithium costarscensis, n. sp. Plate 10, figure 28 



Shell with a long, slender spire of about 12 whorls (tip brok- 

 ed) ; sutures deep but somewhat appressed; the profile of the 



