326 REPORT ON ALBATROSS MOLLUSC A DALL. 



Family NASSID^. 

 Genus NASSA Lamarck. 

 Nassa scissurata Dall. * 



Plate v, Fig. 2. 



Nassa scissurata Dall, Bull. Mus. Comp. Zool., xvm, p. 185, 1889. 



Shell short, conical, glistening:, white, clouded with light brown or 

 buff'; whorls stoat, well rounded; nucleus of two translucent turns, 

 smooth, or transversely slightly wrinkled; remainder, comprising live 

 or six turns, separated by a deep but not channeled suture; sculpture 

 of (on the last whorl about fourteen) stout, rounded ribs, with wider 

 interspaces, completely crossing the whorls, and tine incremental striae; 

 spiral sculpture of (on the last whorl about ten) revolving ridges, faint 

 in the interspaces, strongly ovally noduled on the ribs, three rows 

 showing on the upper whorls; ribs interlocking at the sutures; aper- 

 ture rounded, with its edge continuous and raised, contracted in front 

 of a stout varix, lirate on both sides; a stout tooth on the body and 

 another at the base of the pillar ; a deep groove behind the siphonal 

 fasciole; canal short, strongly twisted; operculum seriate at the sides. 

 Longitude of shell, 12; of last whorl, 8; of aperture, 5; maximum lati- 

 tude of shell, 7.5 mm . 



IIab. — The Antilles and Gulf of Mexico, in 70 to 805 fathoms, rocky 

 bottom; bottom temperature 58°. 5 to 65° F. 



This species is clearly distinguished from N. Hotessieri, which is its 

 nearest relative, by the character of the sutures, which are not chan- 

 neled, by its fewer strongly nodulated ribs, and by the curve of the 

 libs, which in Ilotessieri, as in most ribbed univalves, are convex for- 

 ward on the periphery, and then curve a little backward, while in N. 

 scissurata the curve is in a contrary sense, as is at once evident on com- 

 paring two specimens. The total curve is not great, but quite sufficient 

 to form a marked distinction. 



This species has the bright waxen luster of a deep-water shell, and 

 probably lives in between 7<~> and 200 fathoms depth. Its sculpture re- 

 calls that of N. spinulosa Phil. 



Nassa Townsendi sp. nov. 



Plate xii, Fig. 9. 



Shell small, short, very stout, yellowish white, with six whorls; nu- 

 cleus eroded : transverse sculpture of about sixteen narrow, rounded, 

 low riblets, which extend from suture to suture, but on the last whorl 

 fade away in front of the periphery; the interspaces are nearly twice as 

 wide as the ribs, which in front of the suture have two or three small, 

 prominent nodules coronating the whorls, caused by the intersection 

 of as man) spiral threads, which, however, are faint or obsolete in the 



