CLASS GASTROPODA 
199 
lip callous; columella strongly twisted; canal short, rather wide. Long., 
1.33 ;lat., 0.75 in. (Dali.) 
Type in United States National Museum. Type locality, Cape Espen- 
berg. 
Range. Icy Cape, Arctic Ocean, to Shumagin Islands. 
Described as Buccinopsis canaliculatus. 
Liomesus nux Dali, 1877 
Plate 2, fig. 22 
Proceedings of the California Academy of Sciences, 7 :7. Proceedings of the United 
States National Museum, 24; PI. 38, fig. 7. 
Shell short, very solid, smooth, except for microscopic revolving 
striae, with an ivory-like surface, which in young living specimens is 
covered with a beautifully reticulated, short, velvety epidermis, of a brown¬ 
ish color. The adult shell is white, or with a band of livid purple. Suture 
distinct; spire very short; whorls five, last much the largest, very rotund; 
outer lip thickened, smooth, projecting beyond the columella, whose an¬ 
terior is smoothly and widely twisted, so that a glimpse can be had of 
the interior axis. Column thickened, short, somewhat arcuated, with no 
fasciole. Greatest length, 1.28; end of columella to tip of spire, 1.2; 
width, 0.8; length of aperture, 0.8; spire, 0.5 in. (Dali.) 
Type in United States National Museum. Type locality, Aleutian 
Islands, in 10 fathoms. 
Range. Aleutian Islands to Shumagin Islands, Alaska. Also Japan. 
Described as Liomesus canaliculatus. 
Genus MOHNIA Friele, 1878 
Shell as in Siphonorbis or Plicifusus, but the whole nepionic shell 
smooth (it is sculptured up to the larval whorls in other species) ; oper¬ 
culum coiled, pauci-spiral; radula, with one cusp on the rhachidian and 
two on each lateral tooth ; ovicapsules solitary, as in Tritonofusus. (Dali.) 
Type. Fusus mohnii Friele. 
Distribution. Arctic North America. 
Mohnia robusta Dali, 1913 
Plate 17, fig. 3 
Proceedings, Philadelphia Academy of Natural Sciences, 501. Bulletin 112, United 
States National Museum; PI. 10, fig. 12. 
Shell solid, stout, of about eight whorls, the apical ones being always 
eroded in adult shells; the upper whorls with fifteen to sixteen axial 
rounded, little elevated, nearly straight riblets, which become feebler and 
finally vanish on the last whorl; suture appressed, slightly constricted; 
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