NO. O HARTMAN: SUBMARINE CANYONS 81 



Newport en, 170 m (1), 211 m (4), 272 m (1), 420 m (5), 478 

 m (2), 553m (1), 642m (3). 

 La Jolla en, 793 m (12). 

 Coronado en, 566 m ( 8 ) . 



Prochaetoderma californicum SchwabI, 1963, in press 

 Dumecn, 374m (5), 580 m (6). 



Newport en, 170 m (3), 178 m (2), 478 m (1), 553 m .(10). 

 Coronado en, 566 m (36). 

 Catalina en, 379 m (6). 



Additional Notes on PELECYPODS. 



Dacrydium pacificum Dall, 1916 



Fig. 4a-c. 

 Soot-Ryen, 1955, p. 86 (review of the genus). 



Newport en, 553 m ( 1 ) . 



San Diego trough, 343 m (1), 381 m (1), 420 m (1). 



San Clemente rift valley, 1620 m ( ? 5) . 



All specimens are dead valves, but some fresh as though not long 

 dead. Specific identity has been verified by Dr. Myra Keen, Stanford 

 University and Dr. Harald Rehder, United States National Museum. 

 Its occurrence from the type locality, Bering Sea in 1401 fms, is of 

 some interest since it suggests affinities of the deepwater fauna of 

 southern California with that of Arctic seas. 



Lyonsiella alaskana Dall, 1894 



Fig. 4d. 



(Some of the collections were identified by Dr. Myra Keen). 



Newport en, 553 m ( 1 ) . 



Coronado en, 566 m (3). 



Catalina en, 379 m ( 1 ) . 



This species was first described from the Gulf of Alaska, in 1569 

 fms, in green ooze. Its present distribution is limited to the deeper 

 parts of submarine canyons. The valves are characteristic (Fig. 4d), 

 cordate in shape, thin and delicate, and externally sculptured with 

 radiating ridges. 



Saxicavella pacifica Dall, 1916 

 This species is given special notice because it occurs in peak num- 

 bers at some places. 



Monterey en, 211 m (6). 



Hueneme en, 177 m (99), 373 m (9), 376 m (12). 



