NO. 186:5. M0LLUSK8 OF THE GENUS ALYANIA—BARTSVJI. 349 



ALVANIA ROSANA, new species. 

 Plate 31, fig. 6. 



Shell broadly ovate, yellowish white. Nuclear whorls two and one- 

 half, smooth, well rounded. Post-nuclear whorls well rounded, 

 marked by narrow, well-rounded, somewhat sinuous, almost verti- 

 cal, axial ribs which are about one-third as wide as the spaces that 

 separate them. Of these ribs 24 occur upon the second and the 

 penultimate turn. In addition to the axial sculpture the whorls are 

 marked by low, rounded, equal and equally spaced spiral cords, 

 wliich are a little weaker than the axial ribs. Of these cords 6 occur 

 between the sutures on the second turn and 7 on the penultimate 

 turn, the first being at the summit. These spiral cords are a little 

 narrower than the spaces that separate them. Suture moderately 

 constricted. Periphery of the last whorl inflated, marked by a 

 sulcus which is as wide as the spaces that separate the cords on the 

 psire and, like them, crossed by the continuations of the axial ribs, 

 which terminate at the posterior border of the first basal keel. Base 

 strongly rounded, narrowly umbilicated, very slightly attenuated 

 anteriorly, marked by eight equal and equally spaced spiral cords 

 which are about as wide as the spaces that separate them. Aper- 

 ture broadly oval; posterior angle obtuse; outer lip thick, reen- 

 forced immediately behind the edge by a moderately thick callus; 

 inner lip strongly curved and somewhat reflected over and partly 

 appressed to the base; parietal wall covered ^\dth a moderately tliick 

 callus. 



The type and 72 specimens (Cat. No. 213688, U.S.N.M.) were 

 dredged by the United States Bureau of Fisheries steamer Albatross 

 at station 2901 in 48 fathoms, ofl" Santa Rosa Island, California, on 

 mud bottom, bottom temperature 55°. The type has tlu*ee post- 

 nuclear whorls and measures: Length 2.6 mm., diameter 1.5 mm. 

 Cat. No. 213689, U.S.N.M., contains 45 specimens dredged by the 

 United States Bureau of Fisheries steamer Albatross at station 2902 

 in 53 fathoms, off Santa Rosa Island, California, on mud bottom, 

 bottom temperature 45°. Cat. No. 23762, U.S.N.M., contains one 

 specimen dredged in 30 fathoms off Catalina Island, California, and 

 Cat. No. 46169, U.S.N.M., contains one which was also dredged in 

 30 fathoms oft' Catalina Island, California. 



ALVANIA FOSSILIS, new species. 

 Plate 31, fig. 8. 



Shell broadly ovate, white. Nuclear whorls at least two, having 

 their surface eroded. Post-nuclear whorls almost flattened, marked 

 by rather strong, protractive, axial ribs, of which 24 occur upon all 

 the whorls. These ribs are about one and one-half times as wide 

 as the spaces that separate them and termmate at the posterior edge 



