298 University of California Publications in Zoology [Vol. 23 



3. Seven (15%) of the survey species were found both in the 



bay and outside : 



Spirontocaris cristata Crago franciscorum 



Crago nigricauda Cancer magister 



Crago nigromaculata Cancer gracilis 

 Crago stylirostris 



These seven are really bay species which range outside as far as 

 the environmental conditions correspond in general to those obtain- 

 ing in the portions of the bay in which they range inside. With 

 the exception of Spirontocaris cristata and Cancer gracilis none of 

 these species was taken outside the 30 fathom line, nor, so far as our 

 records indicate, in water of (bottom) salinity exceeding 34.0. Com- 

 prising, on the other hand, nearly two-thirds (63%) of the eleven 

 species taken at more than ten stations, and all of the five taken at 

 about one-fourth of the dredging stations, they should be, and in 

 fact are, fairly well distributed throughout the bay. Crago nigro- 

 maculata is the only one of them failing of record in the upper bay. 



Spirontocaris cristata was taken only three times outside, two 

 specimens at each of two stations, and one at a third, in 8y 2 to 9 

 fathoms (bottom not characterized), in 9^ to 11% fathoms (bottom, 

 "coarse sand and gravel"), and 29 to 36 fathoms (bottom, "refuse 

 and garbage"). In the upper bay, however, Spirontocaris cristata 

 was taken at two stations (1 D and 1 H), in the middle bay at thirty- 

 three (21 D and 12 H), and in the lower bay at twenty-five (10 D 

 and 15 H). The lower bay with its predominantly muddy bottom 

 seemed to be the more favored habitat of this species. Here fourteen 

 and four-tenths specimens per dredge haul were returned as com- 

 pared with two and two-tenths for the middle bay and two for the 

 upper bay. The average per catch with tow-net was, lower bay, four 

 and eight-tenths, middle bay, three and five-tenths, and upper bay, one. 



Cancer gracilis, the only other species found in the bay which 

 ranged beyond the 30 fathom line was taken but twice outside, one 

 specimen in 8 to 9 fathoms, on a bottom of "fine, dark, very clean 

 sand," and two specimens in 39 to 40 fathoms, on "very fine dark- 

 green sand." Although taken in the bay at but one upper, eight 

 middle and three lower bay stations, its distribution was very closely 

 related to that of the preceding species, Spirontocaris cristata, coin- 

 ciding with it at five of the stations from which it was recorded and 

 very nearly at the other nine. Similarly, too, the greater number of 

 specimens per haul was in favor of the stations made on more or less 

 muddy bottoms. 



