504 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxm. 



at the summit. There are no well-defined ribs, the axial sculpture 

 being reduced to mere lines of growth with here and there a weakly 

 impressed area, probably representing an obsolete intercostal space. 

 Sutures strongl}^ impressed. Periphery of the last whorl faintly 

 angulated. Base short, well rounded. Entire surface marked by fine, 

 regular, close, spiral striation. Aperture pyriform, posterior angle 

 acute; outer lip thin, columella somewhat twisted, scarcely re volute 

 at its free end. 



The type has 8i whorls remaining which measure: Length 8.5 mm., 

 diameter 2.7 mm. It and another specimen (Cat. No. 181112, U.S.N. M.) 

 were dredged by the United States Bureau of Fisheries steamer Alba- 

 tross at Station No. 2885 off Oregon, in 30 fathoms, with a bottom 

 temperature of 49°. 



Another specimen (Cat. No. 196222, U.S.N.M.) was dredged at 

 Station No. 2868, off the coast of Washington, in 31 fathoms on gray 

 sand with a bottom temperature of 46.9°. 



The absence of ribs differentiates this form from all the other Pyrgo- 

 lam.2Jros mentioned in this paper. It is allied to two species not yet 

 described, one of which belongs to the Californian and the other to the 

 Alaskan fauna. 



Subgenus PYRGISCUS Philippi. 



Pyrgiscus Philippi, Wieg. Arch., I, 1841, p. bO. — Pyrgostelis Montekosato, Conch. 

 Medit, 1884, p. 89. — Ortostelis Aradas, Atti Dell Acad. Giov. di Catania, 1843, 

 XX. 



Turbonillas having prominent vertical ribs and deeply incised spiral 

 lines, but no varices or internal lirations on the outer lip. Columella 

 usually somewhat flexuous. 



Ti/pe. — Melan'i.a rufa Philippi. 



KEY TO SPECIES OF PYRGISCUS. 



Axial ribs terminatino; at tlie periphery canjieldi. 



Axial ribs passing feebly over the periphery and base of the last whorl. 

 Periphery of the last whorl angulated. 



Ribs retractive morchi. 



Ribs vertical antestrlata. 



Periphery of the last whorl well rounded. 



Adult shell more than 10 mm. long eucosmobasis. 



Ad ult shell less than 7 mm. long tenuicula. 



Axial ribs extending prominently over the periphery and base of the last whorl, 



castanea. 



TURBONILLA (PYRGISCUS) CANFIELDI, new species. 



Plate XLVII, figs. 4, 4ffl. 



Shell slender, elongate-conic, with the posterior half of the exposed 

 portion of the whorls on the spire white and the anterior half chest- 

 nut brown, base white. Nuclear whorls 2|, large, smooth, forming a 



