388 PROCEEDINGS OF THE ACADEMY OF [PaRT II 



denticulata Sowerby do not seem sufficient for a positive determin- 

 ation, 



Epitonium amplum (Gabb) Plate XXXIV, fig. 22. 



Scalaria ampla Gabb, Tr. Am. Philos. Soc, xv, 1873, p. 224 



On the last whorl the ribs become wider downwards, until near 

 the axis they run together. In the intervals two or three low spiral 

 cords may be seen above the much stronger basal cord. There are 

 10 ribs on the last whorl. 



Length 14, diam. 10.8 mm., 4 whorls remaining. 



Type is no. 2823 A. N. S. P. It is from the brown shale east of 

 Guayubin. 



Sthenorytis toroensis Dall, from Limon Bay, has much in common 

 with this species, but the varices are recurved, and there is no bas- 

 al cord. 



Epitonium minutissimum (Gabb) Plate XXXIV, figs. 10, 11, 



Scalaria minutissma Gabb, Tr. Amer. Philos. Soc, XV, 1873, p. 224. 



Two of the twelve ribs on the last whorl are distinctly larger, both 

 higher and thicker. All bear short points near the suture. In the 

 intervals of the major spirals there are several, usually three, smaller 

 spirals, and the whole is delicately latticed by axial threads. 



Length 6, diam. 2.3 mm., 8| whorls remaining. 



Type and 4 other specimens are no. 2824 A. N. S. P. 



Epitonium santodominganum n. sp. Plate XXXIV, figs. 8, 9. 



The shell is imperforate, slender, with about 3| smooth embryonic 

 and 5| sculptured whorls. Sculpture of thin ribs on the spire, some- 

 what thicker on the last whorl, where there are two varices, one near 

 its beginning, the other on the back. There are about 18 ribs in all 

 on the last whorl. The intervals have sculpture of narrow low spiral 

 cords, with several smaller, less distinct threads between them on 

 the last two whorls. The cords slightly crenulate the posterior edges 

 of the ribs. Aperture short-ovate. 



Length 3.9, diam. 1.5 mm. 



Type no. 4064 A. N. S. P.; with Scalaria minutissima Gabb. 



Epitonium amosbrowni n. sp. Plate XXXIV, fig. 7. 



A minute, imperforate, rather thin species, with about 2 smooth, 

 convex embryonic whorls followed by 4J very convex whorls with 

 deep suture. Sculpture of thin, equal ribs each rising in a blunt 

 point at the shoulder, 16 on the last whorl. The intervals have low 

 indistinct spiral cords on the lower half of each whorl, but not ex- 



