126 BuLLKTiN 39 298 



globose form and finer spiral sculpturing. Traces of coloration 

 are still preserved as faint blotches of 3^ellow scattered over the 

 back of the shell. 



Typical Coliimbclla has heretofore not been recorded from 

 beds older then the Pliocene either in America or Europe. 

 Gatun Stage: Zone 5, Red Cliff Creek. 



Genus STROiVIBINA Moerch 

 Strombina ambigua Guppy Plate 10, figure 9 



Colunibella ambigua Guppy, 1866, Quart. Jour.Geol. Soc. London, vol. 



22, p. 288, pi. 16, fig 8. 

 Strombina ambigua Oall, 1903, Trans. Wagner Free Inst. Sci., vol. 3, 



pt. 6, p. 1584. 



This species v^as described from the Bowden beds of Jamai- 

 ca, of Miocene age. Our shells from Costa Rica agree exactly 

 with Gupp3''s figure in the Quarterl}^ Journal. 



A large species of Columbelloid aspect due in large measure 

 to the slight thickening of its outer lip. The sculpture consists 

 of about 25 ribs, which are smooth on the spire whorls and upper 

 half of the last. The base of the last whorl and the canal have 

 in addition about 14 spiral cords. 



Length 27 (7 plus whorls), diameter 10, spire 15, aper- 

 ture 13 mm. 



Gatun Stage: BaJiana River. 



Strombina Lesseplana Brown and Pilsbry Plate 10, figures 13, 20 



Strombina lessepiana Brown and Pilsbry, 191 1, Proc. Acad. Nat. Sci. 



Phila. , vol. 63, p. 352, pi. 25, figs. II, 12. 

 Colunibella {Strombina) gatunensis Toula, 191 1, Jahrb. der K-K, 



Geol. Reichsanstalt, Wien, vol. 61, p. 501, pi. 30, fig. 8. 



An abundant species in the Canal Zone and with the excep- 

 tion of S. ambigua, the largest species of Strombina in the Mio- 

 cene beds of Panama and Costa Rica. The spire is long and 

 smooth, with the exception that the upper sutural zone is usual- 



