358 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 41. 



The type (Cat. No. 195010, U.S.N.M.) was dredged by the United 

 States Bureau of Fisheries steamer Albatross at station 2813, in 40 

 fathoms, on coral sand bottom, bottom temperature 81°, off Galapa- 

 gos Islands. It has almost 4 post-nuclear whorls and measures: 

 Length 2.5 mm., diameter 1.3 mm. 



ALVANIA EFFUSA Carpenter. 

 Plate 32, fig. 5. 

 Alvania effusa Carpenter, Cat. Maz. Shells, 1856, p. 359. 



Shell elongate-conic. Nuclear whorls two, smooth, well rounded. 

 Post-nuclear whorls well rounded, marked by strongly developed 

 narrow, almost vertical, axial ribs of which 14 occur upon the first, 

 16 upon the second to fourth, and 22 upon the penultimate turn. 

 In addition to the axial ribs, the whorls are marked by spiral cords, 

 of wliich two appear upon the first whorl, dividing this into three 

 equal spaces, three upon the second, four upon the tliird, five upon 

 the fourth, and seven upon the penultimate turn, between the sutures. 

 The junctions of the axial ribs and spiral cords form strong cusps, 

 while the spaces inclosed between them are rectangular pits, having 

 their long axes parallel with the spiral sculpture. Suture strongly 

 channeled. Periphery of the last whorl marked by a spiral sulcus, 

 which is about as wide as the sulci occurring between the cords on 

 the last turn of the spire. Base produced anteriorly, moderately 

 rounded, marked by the feeble continuations of the axial riblets and 

 five spiral cords. Aperture oval; posterior angle obtuse; outer lip 

 rendered sinuous by the external sculpture; inner lip strong, curved, 

 slightly reflected over, and appressed to the base; parietal wall covered 

 with a thick callus which renders the peritreme complete. 



The unique type of this species, contained on Tablet 1710, Liver- 

 pool Collection, British Museum, was taken from SpoTidylus at 

 Mazatlan. It has six post-nuclear whorls and measures: Length 

 2.9 mm., diameter 1.5 mm. 



ALVANIA iEQUISCULPTA Keep. 

 Plate 32, fig. 7. 



Alvania sequisculpta Keep, West Coast Shells, 1887, p. 65=Rissoa (Alvania) 

 grippiana Dall, Nautilus, vol. 21, No. 12, 1908, p. 136. 



Shell very elongate-conic, light yellow. Nuclear whorls two, 

 moderately well rounded, marked by six spiral threads, which are 

 about as wide as the spaces that separate them, and numerous 

 slender, closely spaced, axial threads, which are about one-fourth 

 as strong as the spiral threads between which they occur, giving the 

 entire surface a finely reticulated appearance. Post-nuclear wliorls 

 appressed at the summit, with a sloping shoulder which extends 



