1921 J Schmitt: The Marine Decapod Crustacea of California 299 



Crago nigromaculata though lacking in the upper bay, in com- 

 mon with other fairly well distributed bay species, seemed to a 

 certain extent also to prefer more or less muddy bottoms. Of the 

 nineteen stations returning it only two were located on the harder 

 bottom of the western middle bay, and only three on sandy bottoms 

 outside. 



Crago stylirostris, however, although exceeding the range of 

 Crago nigromaculata both within and outside the bay, in direct con- 

 trast to that species was found most frequently as well as most 

 abundantly on more or less hard, sand or sandy bottoms. In the 

 western middle bay Crago stylirostris was taken at twenty-eight 

 dredging stations, in the eastern middle bay at seven, and in the 

 upper and lower bay at only two each. Outside it was returned 

 at eight stations from fine, grey, or coarse sand and pebble bottom. 

 At the more or less muddy eastern middle, upper, and lower bay 

 stations less than eleven specimens per haul were obtained, with one 

 exception at which thirty-three were taken. But of the outside and 

 western middle bay stations thirty returned more than twelve speci- 

 mens each ; of these eight returned more than thirty-three, and five 

 more than fifty specimens. Only three specimens were taken in the 

 tow-net, one at each of three hydrographic stations, one middle, and 

 two lower bay. 



Crago nigricauda and Crago franciscorum are the two most widely 

 distributed decapods in the bay and outside within the 30 fathom 

 line. Both were taken abundantly in all three divisions of the bay, 

 and the latter was also abundant outside. More or less muddy bot- 

 toms returned the greater number of specimens per haul, though 

 otherwise their distribution seemed little affected by the character of 

 the bottom. Of the two Crago nigricauda is apparently more of a 

 "bottom dweller," for even though taken at seven more dredging 

 stations it appeared only about half as often (sixty-nine out of one 

 hundred and thirty-seven times) in the catches of the tow-net. C. 

 franciscorum was the only decapod found in Suisun Bay, as well as 

 Napa Creek, and probably, therefore, can endure water of a lower 

 salinity than any other species listed in connection with the survey. 



Cancer magister, in spite of the fact that it is adapted primarily 

 for living on sandy bottoms, was found well distributed throughout 

 the region covered by the survey though not so abundantly as either 

 of the preceding species. Within the bay it was actually taken more 

 often on more or less muddy bottoms, but with very few exceptions 



