337 



Costa Rica Miocp:nk — Olsson 



smooth within; aperture rounded, with the outer lip strongly 

 oblique. 



Height 15, diameter 21 mm. 



Several specimens of this well-marked species were obtained 

 from the Gatun beds of eastern Costa Rica, in the vicinity of 

 Manzanilla Point. In the Santo Dominican Miocene it is relat- 

 ed to the C Grabajii Maury, but the Costa Rican shell is much 

 lower and more depreSvSed. 



The C. Grabaiii and the manciiiella belong to the group 

 which contains the large, elegant C. Sayana, described by Dal I 

 from deep water off the Hatteras coast. 



Gatun Stage: Coll. 4., East Grape Point Creek. 



Headwaters of Middle Creek. 

 Coll. 5, Red Cliff Creek. 



I mile south of shore, alo?ig' Old Man Sam 

 Creek, ( V eat eh) 



Cayiostoma castilla, n. sp. Plate 15, figure 6, 7 



Shell rather large, in form and sculpture resembling the C 

 philanthropus of the Chesapeake Miocene of eastern United States, 

 but umbilicated; whorls 5 plus (apex broken), flat and forming 

 a broadly conic spire; periphery of the last whorl, subanguiar, 

 due to a broad, cord-like ridge, which ap|)ears as if formed 

 form an overlapping of the base; sculpture of the spire- whorls of 

 fine, alternating and beaded spirals, there being about 13 on each 

 whorl; the base is nearly smooth the spirals being nearly obso- 

 lete or as broad low bands; the spirals about the umbilicus are 

 slightly stronger and obscurely beaded; umbilicus deep and 

 narrow. 



Height 20, diameter 25 mm. 



A large species with an angulated peripher>', fine, beaded 

 spirals above and a nearly smooth base. But a single specimen 



