240 VERRILL 



The spinules are smaller and shorter than in any other North 

 Pacific or Arctic species known to me, and the surface is corre- 

 spondingly more even and finer-grained. 



The two marginal rows and the peractinal row of plates are dis- 

 tinct, but not conspicuous and not very regular. The inferomar- 

 ginals are larger than those of the other rows. They are obliquely 

 placed and transversely compressed proximally, but become more 

 elliptical or rounded and more irregular distally. They bear a close 

 cluster of minute spinules like those of the dorsals. The infero- 

 marginals are smaller and scarcely distinguishable in many places. 

 There are two or three short rows of mtermarginals proximally. 

 The peractinal plates are pretty regular, oblique, mostly rhombic, 

 smaller than the inferomarginals, and spinulated in the same way. 



The adambulacrals bear several close irregular rows of very short, 

 and very small, obtuse spinules, about five to eight in each row, 1 not 

 very unlike in size, and an odd one slightly larger on the inner angle ; 

 the furrow-spine is very small and short. The adoral and oral spines 

 are larger, obtuse, numerous and crowded. 



This species appears to be more distinct from all the other North 

 Pacific forms of the genus than most of those hitherto described, at 

 least from the shallower waters. 



Why Dr. Fisher should have united it with his H. eschrichtii is 

 not easy to understand, for there is no particular resemblance to that 

 species, unless in the short rays; but in this respect the present 

 species exceeds all others except H. tumida. 



From the latter it differs widely in the much finer and shorter 

 dorsal and marginal spinules, in the smaller and closer ossicles, and 

 especially in the very different character of the adambulacral 

 spinules, which are much longer and fewer in H. tumida, and in a 

 single row. The latter, moreover, has a deep concavity around the 

 oral region, in which the jaws and oral plates are so deeply sunken 

 as to be seen with difficulty. Possibly this last character pertains 

 only to the female, as suggested above, but in that case the other 

 characters named are ample for distinguishing the two forms. 



The type of this species was from off Cape Lisburne, Alaska (coll. 

 H. D. Woolfe, No. 12,818, U. S. Nat. Mus.). The specimen figured 

 by Fisher is from the same vicinity. 



1 The figure (pi. LXXXVII, fig. 30) represents these spines as too few and too 

 large. In the specimen figured the spines were badly worn off from most of 

 these plates. 



