176 VERRILL 



Superomarginal spines similar to dorsals, in a simple regular row. 

 Each alternate plate usually bears a large spine. On the disk about 

 fifteen similar spines form a circle around the center, a few spines 

 standing within it. The circle is formed by five pairs of interradial 

 spines and five isolated radials. 



The stout dorsal ossicles are articulated transversely and longi- 

 tudinally, so as to leave large, squarish interspaces, carrying numer- 

 ous small papulae. Minor pedicellarise form dense wreaths around all 

 the dorsal and upper marginal spines at about mid-height. 



Madreporic plate small, flat, with fine gyri. The upper marginal 

 plates are stout, with a broad, obtuse apophysis extending down to 

 the lower marginals, but leaving triangular papular areas between, 

 so that there is a wide naked lane between the upper and lower mar- 

 ginals. A few very large major pedicellariae, with wide spatulate 

 blades, occur on this area. The lower marginal plates are also stout 

 and prominent, each one usually bearing two prominent, subacute, 

 divergent spines, which are nearly as long as the upper ones, but 

 much more slender and twice as numerous. Their large clusters of 

 pedicellarise are mostly confined to their upper side. A less regular 

 row of similar spines is borne on the small peractinal plates, each of 

 which corresponds to about three adambulacrals. 



The adambulacral spines form two very regular rows of rather 

 long, slender, slightly tapered spines, which are often flattened at 

 the tips. Those of the inner row are a little shorter than the outer 

 ones, and more acute. About four of the adambulacral plates cor- 

 respond with one marginal. There is a row of small papular areas 

 between the peractinals. A few small ovate pedicellariae sometimes 

 occur on the adambulacral spines and in the grooves. The small 

 actinal interradial areas bear groups of small, long-ovate major pedi- 

 cellariae of several sizes. 



The very large dermal major pedicellariae on the sides of the rays 

 are not compressed, often nearly as stout as the adjacent spines, and 

 in a profile view the blades are broadly spatulate with abruptly 

 rounded ends, but not unguiculate nor distinctly serrulate, so far 

 as observed. 



Ambulacral grooves wide ; sucker-feet large, placed in four regu- 

 lar rows. 



Queen Charlotte Islands (Dr. G. M. Dawson, Canadian Geological 

 Survey, 1875). 



