324 VERRILL 



disk and on a small triangular interradial area close to the marginals, 

 where the ossicles are more closely joined. They occur regularly 

 on the rest of the disk and on the entire breadth of the rays, except 

 distally, near the tips. There is no median radial band of ossicles 

 differing in size or form from those adjacent and not surrounded 

 by papulae, as is the case in Blakiastcr. 



Seen from the inner side, the dorsal ossicles are all alike, except 

 for a few rather smaller ones, and lie in one plane. Their inner or 

 basal portion is roundish, mostly with six slender, radiating lobes ; 

 or they may be called six-rayed stellate. They are articulated only by 

 the slender ends of these radial lobes, which ordinarily do not show 

 at all on the outer surface. The papular pores are between the radial 

 lobes. 



The inferomarginal plates are short in the radial direction, in the 

 interradial arcs, scarcely exceeding the upper ones, wedge-shaped, 

 thick below. Towards the middle of the rays they become a little 

 oblique, nearly as wide as long, somewhat rhombic, near the tips of 

 the rays they become small, apple-seed shaped, and imbricated 

 obliquely. They are covered with small spinules ; like the upper ones, 

 and mostly bear a small cluster, or short median row, of three or 

 four small, slender, acute spines, much longer than the spinules. 



The triangular interradial areas, below, are flattened, with a 

 pavement of slightly convex, roundish plates, mostly in three pairs 

 of divergent rows parallel with the ambulacra; they are covered 

 with stellate groups of numerous spinules, like those of the marginal 

 plates, but rather longer. An odd interradial plate lies between the 

 ends of the second and third rows. 



The adambulacral plates have a convex marginal series of about 

 four rather long, slender, divergent spines ; and one actinal divergent 

 or stellate group of about six to eight smaller and more slender 

 spines. 



Epioral spines small, slender, and very numerous, in two large 

 series. Perorals a little stouter. 



Apical oral spines four, rather stout, high up on the jaws and 

 nearly concealed by the adjacent epiorals. The adoral adambulacral 

 spines are deep within the grooves, opposite the large and promi- 

 nent jaw-plates, on the edges of the strongly compressed adoral 

 plates, forming a nearly simple curved row. 



When the epioral spines are removed, the two prominent ridges of 

 the actinal face of the jaw-plates are closely united, forming a con- 

 spicuous, elevated, narrowly elliptical carina. 



