NO. 2295. }^'EW NORTH PACIFIC MOLLVSKS—DALL. 327 



Type-locality. — U. S. Fish Commission station 2853, off Alaska 

 Peninsula in 159 fathoms, sand, bottom temperature, 44.8° F. 



BUCCINUM CASTANEUM Dall, 1877. 



This remarkable species was originally described from an ap- 

 parently smooth but very minutely spirally striated specimen from 

 the Shumagin Islands. Later I named a variety with three very 

 prominent spiral cords on the last whorl variety tricarinatum.. I find, 

 however, that Bruguiere named a (Nassa) Buccinum tricarinatum , 

 so I propose for this variety the designation of triplostephanum. 

 As the collection has increased, other specimens of this rare species 

 have come to hand extending the limits of its variability. A form 

 without spiral cords but with (on the last whorl about 10) somewhat 

 irregularly arcuate coarse ribs, and larger than the original type, 

 was collected at the island of St. George (Cat. No. 217152) in Bering 

 Sea, at a depth of 30 fathoms; for this the varietal najne jltictuatuin 

 is now proposed. Still another form from the Unimak Pass, Aleutian 

 chain, in 56 fathoms (Cat. No. 213159) is smaller than the original 

 type and has (on the last whorl about 19) more numerous smaller 

 ribs, which on the periphery are more or less broken up into nodules, 

 and has the line spiral striation fasciculated by the presence at 

 irregular intervals of deeper spiral grooves; for this form the name 

 incisulum is now proposed. In the thickening and arcuation of the 

 outer lip all these forms agree, as well as in the other general char- 

 acters of the type. It would not be surprising if, when a large number 

 of specimens from different localities are brought together, other 

 combinations of the sculptural characters should be revealed. 



BUCCINUM ROSSELLINUM, new species. 



Shell small, very thin, of a dull dark olive color, the suture deep, 

 not appressed; with about six well-rounded whorls, the apex eroded; 

 axial sculpture of line, close, even, silky incremental lines; spiral 

 sculpture of fine, close, equal flattish threads on the spire which 

 later take on the aspect of rather wide flat interspaces between 

 shallow grooves, here and there with a slightly more elevated spiral 

 thread; aperture ovate, outer lip thin, sharp, perhaps not quite 

 mature; inner lip white, erased, pillar short, twisted; canal very 

 short, slightly recurved, wide, with a faint siphonal fasciole; height 

 of shell, 27; of last whorl, 21; of aperture, 14; diameter, 16 mm. 

 U. S. Nat. Mus. Cat. No. 206449. 



Type-locality. — U. S. Fish Commission station 3340, southeast of 

 Chirikoff Island, Alaska, in 695 fathoms, mud, bottom temperature, 

 36.8° F. 



The operculum is subcircular, thin and normal. 



