Rathbun, 1924
Diagnosis: The two dorsal rows of spines and tubercles on the branchial region meet at the outer margin in an acute angle. Interbranchial space not deeply depressed. Rostral teeth as wide as, or wider than, the length of their inner margin.
Description: Specimens of this species were formerly placed with C. tanneri, but the subsequent collection of considerable material demonstrates that the form from northern waters may well be classed as a distinct species.
Carapace more pubescent than in tanneri; the pubescence of tanneri is less dense and more easily rubbed off. Posterior margin of carapace gently arcuate; in tanneri there is a median interruption or small shallow bight. Interbranchial space not so deeply depressed; the urogastric region is defined by a groove on either side; in tanneri the whole region is depressed and narrowly compressed. The two dorsal ridges on the branchial region converge in straight lines and meet in an acute angle marked by a single, though not simple, large spine; in tanneri the ridges meet in a curved line marked by two subequal spines. The posterior of these ridges is formed of bunches of acute tubercles, except the outer one or two on each side, which may be spines or spinous; in tanneri this ridge is composed largely of single spines. The rostral teeth are wider, the width at base being in half-grown specimens as great as the length of the inner margin; in old specimens, greater than the length.
Legs more dilated toward the proximal end. (Rathbun, 1925)
Type locality: south of Pribilof Island, Bering Sea, 2535 m.
Range: Japan - off Sendai (Sakai, 1976a); Kamchatka; Bering Sea; Aleutian Islands; British Columbia, Oregon.