255 Dominican Fossils — Maury 91 



ures 7.5 X5 mm. 



Gabb does not mention any Dominican Nassas. Guppy 

 identified those in Heneken' s collection with the European N 

 incrassata. 



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



Alectrion gurabensis, n. sp. 



Plate 15, Figure 21 



Nassa incrassata Guppy, Quart. Jour. Geol. Soc. London, vol. 32, p. 

 524, 1876. Not N. incrassata Miiller, 



Shell larger and stouter than the other two species, with 

 three smooth nuclear and six sculptured post-nuclear whorls, 

 convex, angidated and shouldered; suture wavy; longitudinal 

 sculpture of narrow, rounded ribs, eleven on the body whorl, al- 

 ternating with wider interspaces; spiral sculpture of three strong- 

 er, more widely spaced threads revolving about the middle of 

 each whorl of the spire with, on the penultimate volution, three 

 additional weaker threads on either side ; on the last whorl there 

 are three or four threads posterior to the three primaries and 

 twelve anterior; anterior sulcus well defined; beak with eight 

 spirals; aperture round; outer lip with eight lirse within; inner 

 lip with a posterior denticle; collumella rugose. Length 11, 

 6 mm. 



This species resembles the recent A. incrassata Miiller, rang- 

 ing from Iceland to the Mediterranean, but that has convex, not 

 angulated whorls, sixteen ribs, a larger callus, and thicker outer 

 lip. Our fossil also recalls A. consensa Ravenel and possibly is 

 the same as the Bowden shell listed by Dall as Nassa near 

 consensa. 



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

 mados. 



Alectrion losquemadica, n. sp. 



Plate 15, Figures 22, 23 



Nassa ambigua Dall (in part), Trans. Wagner Inst. Sci., vol. 3, pt. 6, 

 p. 1584, 1903. Not N. ambigua Montagu. 



