1921 ] Schmitt: The Marine Decapod Crustacea of California 229 



Cancer magister Dana 



Cancer magister Dana, Proc. Acad. Nat. Sei. Phila., 6, 73, 1852; Crust. 

 U. S. Expl. Exped., 1, 151, 1852, pi. 7, fig. 1, 1855; Eathbun, E., The 

 Fisheries of the U. S., see. 1, 770, pi. 261, 1884; Hobnes, Oeeas. Papers 

 Calif. Acad. Sei., 7, 50, 1900; Eathbun, H. A. E., 10, 177, 1904; Wey- 

 mouth, Stanford Univ. Publ., Univ. Ser., no. 4, 42, pi. 9, fig. 25, 1910; 

 Eept. British Columbia Conim. of Fisheries, 1914, 123-129, figs. 1-8; 

 Calif. Fish and Game, 2, no. 1, pp. 22-27, fig. 3, 1916. 

 Characters. — Carapace widest at tenth anterolateral tooth; posterolateral 

 margin behind it entire, without teeth; anterolateral teeth with more or less 

 prominent serrations anteriorly; front not produced, the three median teeth small, 

 the middle one being slightly larger than the others and projecting farther for- 

 ward; outermost pair larger than the others, not reaching so far forward, and 

 separated from them by a considerable interval. Carpus of chelipeds with a 

 single spine above, at distal end; fingers of chelipeds without dark color. Dactyls 

 of ambulatory legs, especially those of last pair, much flattened. 



Dimensions. — Type: length of carapace 120.7 mm., greatest width 177.8 mm. 

 Color. — Light reddish brown, darkest anteriorly, often light orange below; 

 inner sides of the anterior feet and hands crimson (Stimpson). 

 Type Locality. — San Francisco Bay. 



Distribution. — Unalaska to Magdalena Bay, Lower California. Low water to 

 50 fathoms (Eathbun). 



Biological Survey of San Francisco Bay. — Cancer magister is 



quite universally distributed throughout the bay, upper, middle and 



lower, from Carquinez Strait to Point San Mateo (see plate 10), as 



well as outside. On the whole, so far as our survey records would 



seem to indicate, little discrimination is displayed by this species 



between the various kinds of bottom. In the upper bay where the 



bottom is predominantly muddy it was dredged at twelve (54%) 



of the stations. In the middle bay slightly more than half, eighteen 



(53%) of a total of thirty-four stations were in the eastern or muddy 



portion, the balance, sixteen (47%), being in the Raccoon Strait- 



Alcatraz-Golden Gate section with its sand, gravel and rock bottom. 



In the lower bay, however, where the bottom is possibly even more 



pronouncedly muddy than in the upper bay, only five (13%) of the 



hauls returned specimens, quite an evident falling off in the number 



of productive stations as compared with the other two divisions of 



the bay. Outside Cancer magister was obtained from six (35%) of 



the stations, all of which were made on a sandy bottom. Weymouth 



in his "Contributions to the Life-History of the Pacific Coast Edible 



Crab" (1914, p. 124) says: 



Cancer magister shows a distinct preference for sandy bottoms. Occasionally 

 it is found in the fine sand or mud of bays, but such are always recognizable by 

 their discoloured appearance. It is found at times on gravel, but never, as far 



