148 



Bulletin 39 



cribed as sculpturafa a Siliquaria from the lyimon Peninsula, 

 This is united b}^ Dall with the recent West Indian squamata 

 Blainville. I have seen no spicimens and Gabb may have collect- 

 ed it from the true Pliocene beds of the Ivimon Peninsula. 

 Gatun Stage; Island of Bocas del Toro. 

 Port Linton. 



Genus TURRITELLA Lamarck 



Turritella gatunensis Conrad Plate 14, figures 12, 13 



Tiirritella gatunensis Conrad, 1857, Pacific R. R. Report, vol.6, p. 72, 

 pi. 5, fig. 20. 



Turritella conradi Toula, 1909, Jahrb. der K-K Geol. Reichsanstalt, 



vol. 58, p. 694, pi. 25, fig. 4. 

 Turritella gatunensis Brown and Pilsbry, 191 1, Proc. Acad. Nat. Sci. 



Phila., vol. 63, pi. 27, figs. 4, 5, 9. 



The Turritella gatunensis is a medium sized shell seldom 

 over 40 mm in length. The base of the whorl overhangs the next, 

 and each whorl is encircled by a median concave or constricted 

 band. The whole surface it finely sculptured with small spiral 

 threads. The spirals defining the median band are usually slight- 

 ly heavier as well as a few about the upper part of the base. 



The T. gatu7iensis is a common and widely distributed 

 species in the Gatun beds, but always less abundant than the 

 T. altilira or its varities. Like the altilira, zones of T. gatun- 

 ensis are frequent in some localities. 



The T. atacta Dall of the Tampa Silex beds, the T. acropo- 

 ra fossil in the Pliocene of Florida and recent along the east 

 coast of United States and the West Indies, are related 

 species. 



Gatun Stage: Gatun, C. Z. 



Water Cay, Panama. 

 Boucary Creek, C. R. 



