NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 261 



The largest specimen (fig. 127) has almost no trifid stumps, but 

 numerous rough disk spines of very variable length. In fig. 128a 

 is shown one of the most interesting varieties, a specimen from 

 station 5055; in this individual the disk stumps have very long 

 thorns, usually only two, and these are united to each other by a 

 membrane; there are no disk spines; the arm spines are unusually 

 slender and the upper arm plates are unusually long, somewhat 



FlG. 128. OpHIOTHRIX KOREANA. a, PART OF SPECIMEN FROM STATION 5055, FROM ABOVE, X f<~, b, PART 

 OF SPECIMEN FROM STATION 4878, FROM ABOVE, X 8. 



pentagonal with distal angle rounded and proximo-lateral sides 

 longest and concave, rather than straight; the disk is nearly white, 

 the arms very pale brown, with a broad longitudinal white stripe 

 bordered on each side with reddish, faintly indicated on upper side 

 of arm. Another interesting specimen, taken at station 4878, is 

 shown in fig. 12$&: this individual has extraordinarily long and 

 prominent disk spines and the color of the disk is unique, uniform 



