Müller, 1906
Diagnosis
Small member of the rotundata group. Carapace dorsal margin straight, posterior and ventral margins smoothly curved (C. pusilla Habitus 1, C. pusilla Habitus 3). Right asymmetrical gland opening at the tip of a low angled process just below the postero-dorsal corner. Left asymmetrical gland opening just behind the anterior end of the hinge.
Female, frontal organ, undifferentiated, straight and bare (C. pusilla 1).
Male, frontal organ swollen at the end (C. pusilla 3). First antenna "e" seta armature eight pairs of spines giving way proximally to a further ten which alternate (C. pusilla 4).
Remarks
Immediately distinguishable from all other species in the rotundata group by the angled process on which the right asymmetrical gland opens, except for C. macromma (not found in U.K. waters) which is larger and whose left asymmetrical gland opens almost a third of the carapace length posteriorly of the tip of the rostrum.
Distribution
One of the commonest species at deep mesopelagic and shallow bathypelagic depths in all oceans. 60°N-64°S in Atlantic. 1, 2, 3 (R.R.S. Discovery Map).
Type specimens
None designated; status of original material uncertain.
Type locality
Original material from widely dispersed stations in the Indian and Atlantic Oceans.