134 NATURAL HISTORY BULLETIN 



very small, roundish plates that are not much crowded. They 

 bear a very small stellate group of minute spinules, which, on 

 the larger radial plates, form a marginal row of about six to 

 nine, around a central one of the same size or slightly larger 

 and acute. Those on the papular areas, around the madreporic 

 plate and on the central part of the disk are partly larger with 

 larger and more numerous spinules. On the papular areas, in- 

 terradial areas, and near bases of the rays some of them bear a 

 small central spine ; some of these exceeding the diameter of the 

 plate. These are not found much beyond the bases of the rays^ 

 except a few sparsely scattered along the ray, of smaller sizes. 



The papular areas are large and well defined, U-shaped, with 

 two rows of about six or seven pores in each limb. They are 

 slightly raised above the general level. 



The madreporic plate is irregular in form, not very large, 

 deeply grooved, and surrounded by six enlarged parapaxillae. 



The combined jaw-plates are broad-ovate with the oral edge 

 broadly rounded and bearing four rather large and stout, blunt 

 peroral spines ; on one jaw there is a median odd one, deeper in 

 the mouth. The lateral marginal row has six slender spines. 

 Epioral spines are not very numerous, in two or three rows on 

 each side, the anterior pair larger. 



The adambulacral plates have a prominent obtusely angular 

 and rounded inner margin, which bears a row of eight to ten 

 slender graded spines, continued along the actinal edges by 

 smaller spinelets. The actinal face has one rather large and 

 stout, tapered, central spine; some few plates have a smaller 

 secondary spine. 



The interactinal plates form two rows ; counting both ends the 

 first row has eight or ten plates ; the second has about four, with 

 others rudimentary. They are spinulated like the inferomar- 

 ginals and some of the larger ones have a central erect spine. 



No pedicellariae of any kind could be found. 



This is a very distinct species, unless some of the young, with- 

 out discal spines, called mirabilis by Perrier, prove to be its 

 young. Most of them, however, have a very different papular 

 area, when any is visible. The absence of pedicellariae may be 

 merely an individual peculiarity, but is unusual in this genus, 

 with specimens so large. 



