Near Chionoecetes opilio. Carapace a little wider than long (length measured to tip of rostral teeth). The spines in the row leading from the pterygostomial region backward to the branchial region become suddenly larger, the last three or four spines being of considerable size; in opilio these spines do not increase notably in size. Several other prominences of the antero-lateral regions are spinous instead of tuberculous. Outer orbital tooth curved more strongly inward than in opilio, rostral teeth narrower, interspace wider. Spines of legs longer.
Description: The branchial regions are more depressed than in opilio, and in consequence the width is greater; the width exceeds the length, while in opilio the width is subequal to the length. The inclined subtriangular facet of the anterior branchial region is steeper, higher and shorter than in opilio; the highest point is marked by a spine, instead of a tubercle; in opilio, there are no dorsal spines, that is, none above those in the submarginal row. In Chionoecetes bairdi the last (posterior) three or four spines of the pterygostomial-branchial row are notably enlarged; also the outermost of the prominences in the transverse branchial row is spinous or spinulous. The whole animal is rougher than in Chionoecetes opilio. The carapace is narrower across the orbits, the outer orbital teeth are bent inward more; the median emargination of the front is wider and the teeth narrower and with less arched margins, than in opilio. The lateral margins of the crapace is deeply scalloped, this character alone serves to distinguish very young specimens (10 mm and under) from the allied species. Chelipeds and legs more coarsely and abundantly spinous than in the allied species. Male abdomen with sides a little more concave, terminal segment with its free edge more arched, the segment less invaginated in the preceeding segment. (Rathbun, 1925)
Type locality: British Colombia.
Range: Japan - Funka Bay, off Noboribetsu, off Hiroo, off Kitami, off Hirono, and off Kushiro, Hokkaido (Komai et al., 1992); Bering Sea; Bristol Bay (Miyake, 1983); Aleutian Islands; Alaska; British Colombia.