220 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 54. 



and recurved, moderately long; the aperture (including the canal) 

 about as long as the spire. Operculum as in Coins. Dentition (of 

 P. arcticus Philippi) ^:i:^, the cusps of the rhachidian subequal, 

 the middle cusp of the laterals smaller and often variable or bifid. 

 The type of. the radular sac is chrysodomoid. Arctic seas. 



The small size, livid coloration, and heavy shell of the North 

 Atlantic species described by MoUer, is so different from the large, 

 whitish, thin form from the Arctic Ocean and Bering Sea named 

 by Philippi in 1850 Fusus arcticiLS, that I think it best to regard the 

 two as distinct species, though they have generally been regarded as 

 synonymous. 



Subgenus Retifusus Dall. 



Shell of small or moderate size, .with a conspicuous dark usually 

 vernicose peribstracum ; axially plicate, the surface reticulated by 

 sharply incised spiral grooves ; nucleus swollen, chrysodomoid ; outer 

 lip flexuous, slightly reflected, sharp, simple, without internal lirae; 

 canal short, recurved, with the siphonal fasciole indistinct; opercu- 

 lum arcuate with apical nucleus. Bering Sea and north Pacific. 



Type. — Tritonium jessoense Schrenck. 



Ghrysodomus virens Dall, and several new species belong to this 

 group. 



Subgenus Latipusus Dall. 



Shell short and broad, whitish, with a dull slightly villous perio- 

 stracum; arcuately plicate with fine spiral threading; canal and 

 aperture as long as the spire; outer lip strongly flexuous behind, 

 slightly thickened and reflected ; pillar short, smooth, with the body . 

 coated with callus in the adult ; canal short, wide, recurved, with the 

 siphonal fasciole feeble; operculum arcuate, the nucleus apical and 

 in perfect specimens incurved ; the apex of all the specimens is more 

 or less eroded, but appears to have been acute and chrysodomoid. 



Type. — Chrysodomus griseus Dall, Californian coast in deep 

 water. U. S. Nat. Mus. No. 96531. 



This is the buccinoid phase of PUdfusus as Lafisipho is of Colus. 



Subgenus Microfusus Dall. 



Shell small, with a somewhat villous, inconspicuous periostracum ; 

 nucleus smooth, swollen, obliquely tilted, chrysodomoid; subsequent 

 whorls near the apex axially ribbed, the remainder without axial 

 sculpture : spiral sculpture of fine close threading ; suture appressed, 

 spire acute ; aperture shorter than the spire, with a wide, very short, 

 recurved canal; outer lip simple, sharp; pillar without callous de- 

 posit, or marked siphonal fasciole. 



Type. — Chrysodomus acutispiratus Sowerby. Japan, U. S. Nat. 

 Mus., No. 274056. 



