26 Bulletin 29 190 



of type 25, greatest diameter 5.5 mm. Our specimens run from 

 21 to 32 mm. in length and 5 to 7 in greatest diameter. 



The biplicate columella at once places the species in the T. 

 bipa7 r tita group and separates it from the Isthmian T. gatunen- 

 sz's, which it resembles somewhat in ornamentation. 



The type of T. cirrus is from the Rio Amina. 



Localities. — (Exp'd '16) Zone G, Rio Gurabo, at Los Que- 

 mados; Zone I, Rio Cana, at Caimito; and Bluff 3, Cercado de 

 Mao. 



Terebra oligomitra Dall 

 Plate 3, Figure 18 



Terebra (Acus) bipartita Sowerby variety oligomitra Dall, Proc. U. 



S. Nat. Museum, vol. 18, No. 1035, p. 38, 1895. 

 Terebra (Oxymeris) bipartita Sowerby variety oligomitra Dall, Trans. 



Wagner Inst. Sci., vol. 3, pt. 6, pi. 59, fig. 29, 1903. 



This species resembles T. spirifera Dall, but the ornamen- 

 tation is bolder and more striking. As in that species there are 

 four spiral bands between the sutural zones, but the spirals in 

 this shell are of less nearly equal in width and less strongly de- 

 fined. In spirifera the spirals are somewhat stronger than the 

 transverse riblets, but in oligomitra the opposite is true, the rib- 

 lets being very sharp, thin, and well-defined. The three poster- 

 ior spirals of the four lying between the sutures are narrower 

 than the anterior one and tend to group themselves together. 

 Subzonal channels striking. Columella rather long, twisted, 

 bearing two sharp folds. Length of decollate shell (of nine 

 whorls) 36 mm., diameter 8. The type, also decollate, measured 

 38 by 8.5 mm. 



This species attained a somewhat larger size than its nearest 

 ally, T. spirifera. Its biplicate columella places it at once in the 

 T. bipartita group. 



The type locality is the Rio Amina. 



Locality. — (Exp'd '16) Bluff 3, Cercado de Mao. 



