158 



Bulletin 39 



330 



The Banana River beds contain a large species of Polinices 

 which appears to be this Dominican species. It differs from the 

 recent mammillaris Lamarck, of the Costa Rican and Panana 

 coast by its much narrow imibilicns. Its surface is lined with 

 very fine spiral threads. 



Young shells may be mistaken for the subclausa which oc- 

 curs in the same beds, and careful study is sometimes necessary 

 for their separation. The present shell is less heavy, with a 

 higher spire and more convex spire whorls. The umbilicus is 

 much narrower, and a smaller callus on its inner lip which shows 

 but faintl}^ the transverse groove. The surface of subclausa is 

 smooth, but in Stanislas- Meunieri very finely lined with minute 

 spirals. 



Gabb has described from Sapote, Costa Rica, a Natica erni- 

 nuloides which in form resembles young shells of the Stanislas- 

 Meunieri. His figure shows a different shaped umilicus and no 

 transverse groove on the callus of its inner lip. 

 Length or altitute 44, diameter 38 mm. 



Gaiun Stage: Hill la 2^ j, Banana River, C. R. 



Subgenus S^EVERITA Risso 



Meverita iiereldis Maury 



Nevevita iiereidis Maury, 1917, Bull. Amer, Pal., vol. 5, p. 301, pi. 23, 

 figs. 17, 18. 



Our collection from ths Lower Gatun of Red Cliff Creek, 

 contains a fragment of this very interesting species. The N. 

 7iereidis described by Dr. Maury, from the Cercado formation of 

 Santo Domingo, is closely allied to the recent West Coast N. 

 glauca Humboldt. The Miocene nereidis is less broad, with 

 a narrower umbilicus and a larger umbilical callus. 



Gatu7i Stage: Coll. 6^ Red Cliff Creek, C. R. 



