218 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Colus halidonus Dali, 1919 
Plate 13, fig. 12 
Proceedings of the United States National Museum, 56 :318. 
Shell of moderate size, short, stout, white with an olivaceous peri- 
ostracum, with about six whorls, the apex defective, suture distinct, not 
appressed; axial sculpture of (on the penultimate whorl, about 16) fine 
channeled grooves with wider flat interspaces, of which two behind the 
suture are wider than the others; on the base the posterior edge of these 
interspaces is raised and the anterior lowered to the level of the bottom 
of the grooves giving the effect of narrow threads with much wider in¬ 
tervals; these two varieties of sculpture cover the whole of the shell; 
aperture wide, the outer lip somewhat reflected, body erased, pillar short, 
gyrate, axis pervious; canal short, very wide, recurved and flaring an¬ 
teriorly; operculum normal. Height of shell, 35; of last whorl, 27; of 
aperture, 20; diameter, 20 mm. (Dali.) 
Type in United States National Museum, No. 213250. Type locality, 
off Destruction Island, Washington, in 516 fathoms. 
Range. Pribilof Islands, 81 fathoms to Monterey Bay, California, in 
633 fathoms. 
SECTION LIMATOFUSUS Dali, 1918 
Colus trophius Dali, 1919 
Plate 13, fig. 10; Plate 7, fig. 3 
Proceedings of the United States National Museum, 56:319. Bulletin 112, United 
States National Museum; PI. 10, fig. 9. 
Shell of moderate size, short, white, with a pale olivaceous periostra- 
cum with more than five well-rounded whorls, the apex eroded; suture 
distinct, not appressed; axial sculpture of faint concavely arcuate incre¬ 
mental lines; spiral sculpture of (on the penultimate whorl, about a 
dozen) sharp, narrow, channeled grooves, with considerably wider flat 
interspaces, which, on the last whorl, are more or less divided by a shallow 
median groove; this sculpture is practically uniform over the whole sur¬ 
face ; aperture wide, simple, white within; outer lip slightly reflected, thin, 
body erased; pillar short, straight; axis pervious. Height of shell, 32; of 
last whorl, 26; of aperture, 21; diameter, 19 mm. (Dali.) 
Type in United States National Museum, No. 122628. Type locality, 
United States Fish Commission Station 3071, in 685 fathoms, off Sea 
Lion Rock, Washington. 
Range. Eastern Bering Sea to Pribilof Islands to San Nicolas Island, 
in 1,100 fathoms. 
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