202 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Mohnia exquisita Dali, 1913 
Plate 17, figs. 4, 5 
Proceedings, Philadelphia Academy of Natural Sciences, 502. Bulletin 112, United 
States National Museum; PI. 10, figs. 10, 11. 
Shell delicate, white under a greenish periostracum, with about seven 
whorls; suture not appressed; axial sculpture of incremental lines which 
cut the spiral keels and minutely serrate their edges occasionally; spiral 
sculpture, fundamentally of two prominently elevated keels; one at the 
shoulder recurved, the other vertical to its base; with ten or twelve not 
prominent spiral cords on the base. In one specimen the space between 
the keels has no spiral sculpture, in another there are one or two minor 
keels and numerous faint spirals; this specimen also has a minor keel 
marginating the base. Aperture rather small, the outer lip sharp, thin, 
modified by the keels; inner lip erased, white; pillar gyrate, minutely 
pervious; canal short, wide, hardly recurved. Operculum with subspiral 
nucleus and much transparent enamel on the margin of the proximal 
surface. Length, 31; length of last whorl, 20; maximum diameter, 
14 mm. (Dali.) 
Type in United States National Museum. Type locality, Bering Sea, 
off Koniugi Islands, in 1,766 fathoms. 
Range. Bering Sea, off Koniugi Island, Aleutians, in 1,766 fathoms. 
Genus ANCISTROLEPIS Dali, 1894 
Shell buccinoid, with a short twisted canal; operculum straight, claw¬ 
shaped, concave, with apical nucleus; penis on a short stalk with the 
distal extremity enlarged, foot-shaped, solid, without curved or attenuated 
point. (Dali.) 
Type. C. eucosmius Dali. 
Distribution. Bering Sea to San Diego, California. 
Ancistrolepis eucosmius Dali, 1891 
Plate 25, fig. 7 
Proceedings of the United States National Museum, 14:187; 17; PI. 29, fig. 7, 1894. 
Shell white, solid, strong, seven-whorled, with a lamellose epidermis 
raised in lines with spaces between them along the incremental lines, the 
edges of the lamellae fringed with projecting points. Upper whorl with 
a space in front of the suture and three strong sharp carinae, the first 
interspaces wider than the others; on the first whorl are seven or eight 
spirals, feebler anteriorly; epidermis yellowish olive, throat and pillar 
white, canal very short, operculum straight, unciform. Length of shell, 
33; of aperture, 14; breadth, 18 mm. (Dali.) 
[ 202 1 
