365 



Costa Rica Miocene— Olsson 



93 



Olivella muticoides Maury, 1917, Bull. Amer. Pal., vol. 5, p. 232, pi. 

 II, fig. I. 



A broad, chubby species with a spire of moderate length. A 

 large, thick callus is formed about the upper part of the inner 

 lip, which spreads partly over the back of the penultimate whorl, 

 giving to it a hump-back appearance. Measurements of our 

 Costa Rican shell run as follows: 



Length 17, diameter 7, last whorl 14, spire 6.5 mm. 



13 6.5 II 5-5 nim. 



Gatun Stage: Coll. 5, Red Cliff Creek. 



Coll. 4., East Grape Point Creek. 



OisveiSa Boussaci Cossmann, variety Plate 7, figures 15, 16 



Olivella Boussaci Cossmann, 1913, Journ. de Concli34iologie, vol. 61, 

 p. 60, pi. 5, figs. 16-19. 



The Olivella i^idivisa Guppy (Proc. U. S. Nat. Mus., vol. 

 19) P- 308, pi. 30, fig. 10) from Jamaica and Olivella Boussaci 

 Cossmann from Martinique, belong to a closely related series 

 characterized by their high and sharply pointed spire. The 

 main difference seems to be that of size. The indivisa has a 

 length of 6.5 mm., the Boussaci oi 9 mm. The Costa Rican shells 

 are generally larger and when full-grown, often 13 or more mm. 

 in length. 



Often verj^ common. 



Length 13, diameter 5, last whorl 10, spire 6.5 mm (6 

 whorls) 



Gatun Stage: Hill la, Banana River. 



Hill J, Banana River. 



Olivella limonensis, n. sp. Plate 7, figures 19, 20 



Shell short and plump, with a small, broad, conic spire; 

 whorls about 5, separated by deep sutures; last whorl very large, 

 broadly cylindrical in form and slightly contracted in the middle; 

 the inner lip has a wide callus, somewhat heavier above, with 5 



