Benham. — Stellerids and Echinids from the Kermadecs. 157 



in length, but the tip is brelcen, so that probably it is really twice the 

 diameter of the disc. There are also four other specimens in alcohol. 



The circular disc is covered with larger and smaller subcircular plates. 

 There is a distinct centrale, with convex roughened surface, surrounded 

 by 5 quite small interradial scales, and then 5 larger radial plates, flat, but 

 with the distal margin somewhat raised, so as to form a convex promi- 

 nence ; coloured pinkish. These radial plates are separated from one another 

 by interradial rows of small convex plates. An outer circle of 10 flat plates, 

 with prominent outer margins, radially and interradially placed with 1 or 2 

 small convex plates between them. The adradials of 2 neighbouring arms 

 are separated by 1 large subquadrate plate (fig. 20, m), with its longer axis 

 tangential and the outer border somewhat raised ; and 3 or 4 smaller 

 plates along its mesial margin separate it from other plates of the disc. 

 In one specimen the number of smaller jJlates on the disc is less than in the 

 one figured. 



Fig. 18. Fio. 19. 



Ophiura kermadecensis. 



Fiir. IS. Abactinal surface of a portion of disc and base of one va,y (x 10). 

 Fig. 19. Actinal surface of portion of disc and base of rays (x 12). 



The adradials are exposed, touch one another, and are somewhat pyri- 

 form, with a rounded, raised convexity on its distal margin, which, as in 

 the other plates, is pinkish and roughened. 



The interbrachial area is occupied by one large quadrate, vertically 

 disposed, plate (fig. 20, i.h.), edged on each side by a long narrow plate, and 

 below by 3 rounded plates, which are interposed between it and the oral. 



The orals are large, 5-sided, the radial axis being nearly twice the trans- 

 verse. The two proximal edges are short, and enclose an angle directed 

 towards the mouth. The lateral margins are long and nearly parallel to 

 one another, and the distal or outer edge is convexly rounded. The oral is 

 thrust outwards from the mouth so that its distal margin reaches the edge 

 of the disc, leaving the whole of the 1st and 2nd adambulacrals {i.e., thf> 

 angle-piece and side mouth-plates) exposed. 



There are 4 small quadrate buccal papillae on each angle-piece ; a 

 median and a pair of lateral angular papillae ; no teeth and no dental 

 papillae. 



The arm is cylindrical, tapering, nearly circular in section, inserted 

 in the margin of the disc, with a comb of short spines on each side of the 

 base. This comb consists of 7 spines, of which the lowest is the smallest ; 

 they are conical and sharply pointed. The inner series consists of 5 spines. 



