70 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 27 



Redondo, San Pedro, Newport canyons, the San Diego trench, La 

 Jolla and Coronado canyons, all longshore. One notes a conspicuous 

 increase in numbers in Redondo canyon, partly because this was the 

 best sampled of all canyons, and because it extends from shallow, 57 

 meter, shelf depths where specific categories include shelf species, 

 through slope and basin depths, or a total of about 700 meters vertical 

 depth, and therefore includes faunal components of all depth categories. 

 If other canyons with comparable depth ranges had been sampled 

 as completely, it is possible that comparable high numbers might 

 have been encountered ; this possibility merits exploration for future 

 programs. 



An abrupt faunal break is noted in going from longshore to offshore 

 canyons, as from Coronado to Santa Cruz and Catalina canyons, 

 with specific numbers 352 to 375 (see below). These species are 

 components of an outer fauna and again show vertical zonation. 

 Another break at San Clemente rift valley reflects a change in physical 

 characters of the bottom, from mud to rock, as well as mechanical 

 difficulties of recovering samples of any size. Tanner canyon, though 

 sampled with few probes, shows a sizeable increase of specific cate- 

 gories, those numbered 390 to 401 (below) not previously encountered. 

 More complete coverage of these outer canyons will doubtless reveal a 

 considerable addition to diversified groups, and many species not pre- 

 viously known. 



The listing has further interest in that it reveals the considerable 

 number of species present in all or most canyons. 



i 



