292 University of California Publications in Zoology [Vol. 23 



forty-three (23%) to the region south of it, while one hundred and 

 ten (61%) range both north and south. 



Biological Survey of San Francisco Bay. — Geographically the 

 species taken in connection with the survey (bold face type in the 

 preceding lists) fit very well into the scheme outlined above. This also 

 holds true if the species reported from the region covered by the 

 survey (the bay and that portion of the Gulf of the Farallones lying 

 south of the Farallon Islands) but not taken in course of it (marked 

 with an * in the preceding lists) are included, as shown in the follow- 

 ing summary : 



Summary of Geographical Distribution of the Biological Survey Species 5 



Plus those 

 reported from 

 Only, = 46 region but not 



taken during 



Species peculiar to San Francisco Bay (Pinnixa Survey, = 70 



franciscana) 1 ( 2%) 1 ( 1%) 



Species which on west coast of North America are 



confined to California waters 4 ( 9%) 6 ( 8%) 



Species ranging north of survey region 40 (87%) 57 (81%) 



Species ranging south of survey region 42 (91%) 65 (93%) 



Species ranging both north and south 37 (80%) 53 (76%) 



Species finding the northern limit of their range 



in the Bering Sea 3 (6%) 5 ( 7%) 



Species finding the northern limit of their range 



in the Aleutian-S.E.Alaska stretch 19 (41%) 28 (40%) " 



Species finding the northern limit of their range 



in the British Columbia-Oregon stretch 15 (33%) 19 (27%) 



Species finding the southern limit of their range 



in the Coronados-Magdalena Bay stretch... 15 (33%) 22 (31%) 



Species finding the southern limit of their range 



in the Gulf of California or beyond 5 (11%) 8 (11%) 



Species occurring only in the stretch between the 



Aleutian Islands and Magdalena Bay 38 (83%) 57 (81%) 



Species also reported from the western North 



Pacific chiefly from Japan 8 (17%) 9 (13%) 



Species also reported from the Atlantic littoral 



(Crangon dentipes) 1 ( 1%) 



Species having a bathymetric range exceeding 



500 fathoms 2 ( 3%) 



Ecologically only the species taken in the course of the survey 

 operations will be considered, and then only in a very general way. 

 Future collecting will unquestionably considerably alter the local dis- 

 tribution patterns, as at present known, for a number of the species ; 

 for aside from the fact that only forty-six 5 (66%) of the total seventy 



s Through an unfortunate oversight Cancer gibbosulus was omitted from this 

 discussion. Of this species three specimens were taken, outside, at station D 5790, 

 33 to 35 fathoms, bottom "very coarse variegated sand, with a small proportion 

 of fine sand." 



