Holthuis, 1991
Diagnosis:
The rostrum is a low blunt angle in the median part of the anterior margin of the carapace, being overreached by the eyes with practically their full length. The eyes are triangular with a blunt top. The antennal angles are low, rounded, without tooth. Antennular peduncle only slightly longer than antennal peduncle.
Third maxilliped with ischium and merus strongly widened to form a kind of operculum; the distal three segments much narrower, each about twice as long as wide. Large chela in adult male with a small concavity above the base of the fixed finger. Carpus slightly shorter than palm, about as high as long. Lower margin of merus with a broad forward directed hook-shaped process, which ends in a triangular top.
Telson about as long as wide, gradually narrowing posteriorly: the convex lateral margins merge evenly with the posterior margin. Each posterolateral angle bears two very small denticles, no median denticle present. Endopod of uropod broadly oval, slightly longer than telson.
Type:
Type locality (for C. affinis and thus also for C. biffari): "Point Loma, Calif." ( = Point Loma near San Diego, southern California, USA). Lectotype male in USNM, no. 86810; 2 paralectotypes, probably lost.
Geographical Distribution:
Eastern Pacific region: Santa Monica Bay (California, USA) to San Quintin Bay (N.W Baja California, Mexico).
Habitat and Biology:
On open beaches with a rocky boulder-covered shore (Frey, 1971: 9). The species thus has a preference for a different habitat from those chosen by C. californiensis and C. gigas (see there). The species constructs rather complicated burrows in the soft sandy substratum.
Size:
Total body length 2.5 to 6 cm.
Interest to Fisheries:
In California the species is used as bait together with C. californiensis and C. gigas, and in the accounts of the bait fishery the three are usually treated together. C californiensis is the most important of the three (see there for further details). The burrows of C. biffari are often among rocks, which first have to be removed before digging can start.