1921 ] Schmitt: The Marine Decapod Crustacea of California 225 



lighter, more yellowish tinge; the under parts are yellowish white spotted with 

 red, a coloration not found in any other species of Cancer examined (Weymouth). 



Type Locality. — San Francisco Bay. 



Distribution. — Queen Charlotte Sound, British Columbia, to Magdalena Bay, 

 Lower California. Shallow water to 7 fathoms (Eathbun). 



Bemarks. — From Weymouth (1910, p. 47) I have taken the following: 



There is considerable variation in this species and apparently a tendency 

 toward two types, the extremes of which might readily be taken as a separate 

 species. By far the greater number — which I would consider typical C. antennarius 

 ■ — have a smooth carapace devoid of hair except in the very young, 15 mm. and 

 less in width which exhibit a few coarse hairs. A small number show a tendency 

 toward hairiness and roughness of the hand, the extreme type of which is rep- 

 resented by a young female, measuring 46 by 50 mm. In this the whole cara- 

 pace is densely pubescent (typical specimens of half the size show a perfectly 

 bare carapace) and on the summits of the areolations, which are more marked 

 than in the typical form, there are bunches of larger and stouter hairs. The 

 granulations on these elevations are coarser than on the rest of the carapace, and 

 in some cases pass into small spines. The anterolateral teeth do not differ 

 markedly from the typical form except in being more thickened and in having 

 the teeth spiny-pointed. The frontal teeth are more acute and thicker than is 

 common in C. antcnnarius, especially those lying on either side of the median tooth, 

 The tips of the basal joint and of the adjoining tooth on the lower orbital margin 

 are more acute than in typical C. antcnnarius of the same size. 



The chelipeds and ambulatory legs are pubescent, as is the case with the 

 carapace. The carpus of the chelipeds is marked with several costae bearing low 

 spines and rows of hairs; these costae are generally indicated in the typical form 

 by a line of slightly coarser granulations. There is an acute tubercle above the 

 hinge, a strong spine at the inner angle, and a well marked spine below this. These 

 spines are present in some typical C. antennarius of the same size, but the lower 

 spine is more generally lacking and never of as great size. The hand is marked 

 with two superior and five external earinae, all formed of rows of hairs and 

 spines, the spines in the upper earinae being much longer and more pronounced. 

 In typical C. antennarius of the same size these earinae are more or less well 

 marked by rows of granulations. 



This specimen is, as I have said, the extreme of divergence from the typical 

 form; other smaller individuals show the same pubescence, some have the same 

 extreme type of areolation, notably a larger female from San Diego, the only one 

 not from Monterey Bay here considered. Many young show roughness of the hand, 

 but no other specimen combines as many of these characters. 



The total of these variations from the typical form of C. antennarius might 

 merit specific distinction were it not for certain other facts. All specimens in 

 which I have noticed these characters in any marked degree are immature females. 

 Though they differ from typical forms of the same size, and therefore presumably 

 of similar age, certain of the characters, chiefly the roughness of the hand and 

 the pubescence of the carapace, vary with age in the typical form, being more 

 apparent in the young, so that these differences though apparently much greater 

 than those due to age cannot be said to be of a dissimilar kind. Again, in the 

 typical adult, the female has a more convex and deeply areolated carapace than 

 the male, which raises the question whether the difference in this character may 

 not be, in part, sexual. 



Miss Eathbun has informed me that she has examined very hairy specimens 

 of about the size described, 40 and 50 mm., from La Jolla and San Diego, which 

 she considered as a variety of C. antennarius. Sufficient material may establish 

 this variety, but the collection at hand does not seem to warrant it. 



See also Remarks under C. gibbosulus. 



Biological Survey of San Francisco Bay. — Cancer antennarius, the 

 "rock crab," is only recorded from the middle bay and particularly 

 from that section lying between Sausalito, Fort Point, and Point 

 Bonita, or in the words of Stimpson (Proc. Calif. Acad. Sci., 1, 88, 



