7© Bulletin 29 234 



Genus Marginella Lamarck 



Marginalia coniformis Sowerby 

 Plate 11, Figures 5, 5a 



Marginella coniformis Sowerby, Quart. Jour. Geol. Soc. London, vol. 



6, p. 44, 1849. 

 Marginella coniformis Guppy, Quart, Jour. Geol. Soc, vol. 22, p. 288, 



pi. 17, fig. 2, 1866. 

 Marginella coniformis Gabb, Trans. Anier. Phil. Soc, vol. 15, p. 221, 



1873- 

 Marginella coniformis Guppy, Quart. Jour. Geol. Soc. vol. 32, p. 528, 



1876. 

 Marginella coniformis Guppy and Dall, Proc U. S. Nat. Mus., vol. 



19, no. 1110, p. 309, 1896. 

 ? Marginella coniformis Brown and Pilsbry, Proc. Acad. Nat. Sci. 



Phila., p. 348, pi. 24, fig. 12, 191 1. 



This is the commonest Dominican Marginella. Large shells 

 measure 25 X 13.5 mm. Guppy's Cumana specimen is M. cincta 

 Kiener, and that from the Caroni series, Trinidad, is Persicula 

 near obesa. It does, however, occur at Bowden and Gatun; but 

 Brown and Pilsbry 's figure of a variety also from Gatun is re- 

 markably unlike Guppy's illustration of M. coniformis. 



The Dominican fossil is undoubtedly the ancestor of the 

 shorter and more cylindrical M. guttata Dillwyn, living in the 

 West Indies. 



Localities. — (Exp'd '16) Bluff 1, Cercado de Mao; Zones 

 D and E, Rio Gurabo at Los Quemados. 



Margi?iella Christineladdce , n. sp, 



Plate 11, Figure 6 



Shell slender, elongate, four-whorled, smooth and polished, 

 spire very low; aperture nearly as long as the shell, narrow; 

 margin of outer lip thickened, smooth within; inner lip of adult 

 shells with a thin callus extending to the tip of the spire, colum- 

 ella with four plications, the three anterior oblique, the posterior 

 transverse, lying at the center of the inner lip. Length of largest 

 shell 19, width 9 mm. 



