Dana, 1854
Diagnosis:
Rostrum hardly noticeable, a slight angle in the anterior margin of the carapace. Eyes triangular, reaching with their full length beyond the rostrum. Antennal angles rounded, without spine. Antennal peduncle somewhat shorter than antennular.
Third maxilliped with merus and ischium strongly widened to an operculum; last three segments far narrower, each about twice as long as wide. Large chela of adult male with a distinct concavity in the anterior margin of the palm above the base of the fixed finger; this concavity absent or inconspicuous in females and juvenile males. Carpus about as long as the palm, and about as high as long. Merus with a distinct broad and bluntly truncated process in the basal part of the lower margin; in the female this process is more in the shape of a triangular tooth.
Telson about quadrangular, longer than wide and slightly and gradually narrowing posteriorly; the posterolateral angles are broadly rounded; the posterior margin shows a small triangular tooth in the middle; no other teeth or spines are present. Endopod of uropod squarish with rounded angles, slightly longer than the telson.
Type:
Type locality of C. californiensis: "California". Type material in USNM, now lost.
Type locality of C. occidentalis: "This species lives in the holes which are seen in such numbers at low water on the smooth sandy beaches near the entrance of San Francisco Bay", California USA. Type material now lost.
Geographical Distribution:
Eastern Pacific from Alaska (USA) to northwestern Baja California, Mexico.
Habitat and Biology:
In tidal flats of sand and mud on the sea coasts and in estuarine areas. The animals make their burrows in the soft substrate.
Size:
Total body length up to about 11.5 cm.
Interest to Fisheries:
The species (together with C. biffari and C. gigas) is collected as bait for fishing along the California coast, and sold as such in bait shops The animals are dug out with spades and forks, or by "stomping the mud over the burrow entrance which puddles the mud, seals off the burrow, and forces the shrimp to swim to the surface where it can be easily picked up" (Turner and Sexsmith, 1964: 37).