Anterior marginal carina ponticulate dorsally, but disconnected ventrally to form a row of short spines. Ventromedian carina produced to run concentric to the anterior margin. Distal process of male copulatory appendage subtriangular with a deep, angular concavity on the posterior side.
A marine sublittoral species typically living on sand or silt substrates at depths of 2-60 metres.
There appears to be some variation in the development of the carinae in this species, which may be related to the calcification of the carapace as a whole.
Baird's original description and illustration were of a worn or poorly calcified specimen, which tended to mask the true differences between this species and C. carinata (Roemer). Athersuch & Whittaker (1987b) showed C. bairdii Uliczny, 1969 and many records of C. antiquata (sic) from the Mediterranean to be conspecific with C. whitei as is Brady's Cythereis aspera (1865) from the Pleistocene Nar Valley deposits of Norfolk.
On British coasts (mostly in the south), the French Atlantic coast, and throughout the Mediterranean.