172 VERRILL 



1 : 8. It was taken in 25 fathoms, off Victoria, British Columbia, and 

 was sent to me by Dr. C. F. Newcombe, from the Provincial 

 Museum of British Columbia. 



It agrees well with the specimen from Departure Bay, in nearly 

 all characters, except those apparently due to greater age. The five 

 rows of large dorsal spines are pretty regular and are arranged as in 

 the latter, as are the marginal and ventral spines. As in the smaller 

 specimen, there are but three rows of ventral spines, standing in 

 the same way, in short oblique groups of three, but these spines are 

 relatively longer, being nearly as long as the upper marginals. 

 Major pedicellariae are of different sizes and forms, but mostly large, 

 scattered on the back and sides, as already described. The large 

 denticulate form is most numerous. 



Alcoholic specimens of this species were also obtained by the Har- 

 riman Expedition (pi. xxrv, figs. I, 2). These have the rays plump 

 and rounded. The wreaths of minor pedicellarise on the dorsal and 

 lateral spines are so large that they are nearly or quite in contact, 

 over much of the surface. The ambulacral feet are large and 

 crowded. The spines are arranged nearly as in the dry specimen 

 described above. 



This species is evidently closely allied to O. dawsoni, which I for- 

 merly supposed to be merely the young. But the latter has much 

 fewer dorsal and lateral spines and plates, owing to the relatively 

 larger size of the latter. This is especially noticeable when the distal 

 parts of a ray of each are compared, where of the same size ; for the 

 present species has at least twice as many plates and spines in the 

 same space. The forms of the spines and pedicellariae are somewhat 

 different, though similar. The arrangement of the adambulacral 

 and interactinal spines is nearly the same in both, when of similar 

 size. The larger, lateral, spatulate pedicellariae are more spatulate 

 or lyrate and longer in dawsoni, but I have found, in the latter, none 

 of them serrate or unguiculate, while in this some occur with three 

 or four small interlocking apical teeth. 



This species is remarkable for its thick and enlarged dorsal 

 plates, which are united so closely together that the papular areas 

 are mostly small. The small interpolated ossicles are flat and angular. 

 The marginal and interactinal plates are also unusually thick and 

 convex. 



Yakutat, Alaska (Prof. W. R. Coe, Harriman Expedition) ; 

 Queen Charlotte Islands (Canadian Geological Survey, 1878) ; 

 Departure Bay, British Columbia, 18 fathoms (C. H. Young, Cana- 



