1913.] Clark, Echinoderms from Lower California. 211 



differences which show that we are dealing with two species. The general 

 appearance is dissimilar because the disk-scales of rucjosa are fewer and much 

 more swollen, and the arms, while fully as short, are much more slender. 

 The arm-spines too are pointed and the upper arm-plates and oral shields 

 have a different shape. Apparently the tentacle pores do not continue to 

 the tip of the arm in rugosa but there seem to be more than in oligopora. 



This new species is quite unlike any yet recorded from the western 

 Pacific ocean and is not likely to be confused with any of them. It was 

 taken, unfortunately, at only one station. 



Station 5683. Off Cape St. Lucas, Lower California, 630 fms. Bottom 

 Temp., 39.1. Two specimens. 



Ophiocten pacificum. 



Liitken and Mortensen, 1899. Mem. M. C. Z.. Vol. 23, p. 131. 



This is apparently one of the commonest ophiurans of the North Pacific 

 ocean, as it has been found in numbers by the 'Albatross' at numerous 

 stations from Ecuador to Washington, and in Japanese waters as well. 

 Most of the specimens in the present collection are in very poor condition 

 and are not noteworthy. 



Station 5673. Off Pt. San Tomas, west coast of Lower California. 

 1090 fms. 



Station 5688. Off Cedros Island, west coast of Lower California, 

 525 fms. Bottom Temp., 39.9. 



Station 5689. Off Rosario Bay, west coast of Lower California, 879 fms. 



Station 5691. Off Pt. San Tomas, west coast of Lower California, 868 

 fms. Bottom Temp., 37.2. 



Station 5692. Off Pt. San Tomas, west coast of Lower California, 

 1076 fms. Bottom Temp., 37.1. 



Station 5693. Northwest of San Nicolas Island, California, 451 fms. 



Station 5694. Southwest of Santa Cruz Island, California, 640 fms. 



Station 5695. Southwest of Santa Rosa Island, California, 534 fms. 

 Bottom Temp., 38.9. 



Bathymetrical range, 451 to 1090 fms. Temperature range, 39.9- 

 37.1. 



Two hundred and thirty -three specimens. 



