A large species. Carapace with a subrectangular profile, dorsal margin almost straight and parallelled by the ventral margin apart for a very slight concavity in the latter (C. macrocheira Habitus 1, C. macrocheira Habitus 3). Carapace shape sexually dimorphic. Female, postero-dorsal corner tightly rounded through about 80°, posterior margin is bowed symmetrically, curving smoothly into the ventral margin, rostra are curved. Male carapace with straighter posterior margin and more angled posterodorsal corner, rostra are straighter. Sculpturing, when present, is a pattern of concentric striations.
Female, frontal organ partially differentiated, stem subequal to first antenna, capitulum drooping, finely spinose and rounded (C. macrocheira 1). First antenna clearly segmented, the second podomere carrying moderately long hirsute dorsal seta, "e" seta is just over double the lengths of the sensory setae. Second antenna endopodite with finely spinous "b" seta double the length of "a" seta and almost as long as the second podomere (C. macrocheira 2).
Male, frontal organ, capitulum down-turned, spinose basally, slightly curved and round ended (C. macrocheira 3). First antenna "e" seta armature 29 pairs of basally pointing spines (C. macrocheira 4). Second antenna right-hand endopodite with large hook appendage with two right-angle bends (C. macrocheira 5), left-hand hook appendage angled once.
The juveniles of this species have antero-ventral and antero-dorsal regions enlarged; their unusual appearance misled Fowler, 1909 into describing them as a separate species C. zetesios.
Recorded from all oceans. Juveniles are often caught at shallow mesopelagic depths, but the adults occur in the deep mesopelagic and bathypelagic. 49°N-34°S in Atlantic. 1 (R.R.S. Discovery Map).
None designated; status of original material uncertain.
Originally described from material collected in both the Indian and the Atlantic Oceans between 43°N and 34°S.