189 Dominican Fosslls — Maury 25 



Terebra (Oxymeris) bipartita (Sowerby) variety spirifera Dall, 

 Trans. Wagner Inst. Sci., vol. 3, pt. 6, pi. 59, fig. 13, 1903. 



Shell of medium size, whorls twelve to fourteen, tapering 

 rapidly to an acute spire; spiral ornamentation slightly more pro- 

 nounced than the transverse. The former consists of typically 

 four (sometimes reduced to three) narrow, flattened bands en- 

 circling each whorl of the spire below the sutural zone. The 

 transverse sculpture consists of many close- set riblets which cross 

 the sutural zones sharply and almost perpendicularly, then swing 

 back a trifle in the narrow subzonal channel, but resume a per- 

 pendicular direction on passing under the four spirals which are 

 wound over the riblets. The columella bears two sharp folds. 

 Specimens range from 25 to 35 mm. The type measured 30X8 

 mm. 



In grouping the Dominican Terebras the presence or absence 

 of columellar plications is of much assistance. Thus all the spe- 

 cimens of spirifera, oligomitra, and cirrus show the two folds on 

 the columella, a character which throws them into the T. bipar- 

 tita group, and differentiates them readily from Toula's Isthmian 

 types. 



Localities. — (Exp'd '16) Bluffs 2 and 3, Cercado de Mao; 

 Zone I, Rio Cana near Caimito. 



Terebra cirrus Dall 

 Plate 3, Figure 17 



Terebra {Acus) bipartita Sowerby variety cirrus Dall, Proc. U. S. 



Nat. Museum, vol. 18, no. 1035, p. 38, 1895. 

 Tecebra {Oxymeris} bipartita Sowerby variety cirrus Dall, Trans. 

 Wagner Inst. Sci., vol. 3, pt. 6, pi. 59, fig. 28, 1903. 



This shell bears a general resemblance to T. spirifera .Dall, 

 but can be distinguished from the latter species from the fact 

 that in this shell the spirals are more numerous (five or more to 

 a whorl instead of four), less raised, more irregular, and have a 

 more crowded aspect. The transverse riblets are low, narrow, 

 with wider interspaces. Columella with two sharp folds. Length 



