The Echinoderm Fauna of South Africa. 243 



first very slightly, but distally more abruptly, to a somewhat blunt 

 tip. Disk and rays, within area bounded by supermarginal plates, 

 covered by numerous low, rounded pseudopaxillae, each -lO-'SS mm. 

 in diameter, the height, little, if any, greater: each carries about 

 ten (6-16) short slender spinelets, some of which form a slightly 

 radiating marginal circle ; these are rather longer than those within 

 it and the latter may be scarcely more than rounded granules; the 

 pseudopaxillae show no regular arrangement. Papulae small, single, 

 numerous. Madreporic body large, nearly 4 mm. across, concealed 

 under some 14 pseudopaxillae of varied size ; the outer margin of 

 the madreporite is less than 3 mm. from the inner margin of the 

 superomarginal plates. The latter are 29 in number on each side of 

 the ray, interradially they are nearly square but conspicuously 

 swollen or elevated at center; distally they soon become longer than 

 wide and less swollen and on the distal half of the arm they are 

 scarcely swollen at all but are evidently wider than long; each plate 

 bears a single large spinelet, which is, in the interradial regions, 1 

 mm. high and basally -5 mm. in diameter and occupies the center 

 of the plate but becomes smaller and smaller distally and is placed 

 more and more near tlie outer (lower) edge of the plate; on most 

 of the proximal plates a second, but much smaller spinelet occurs 

 on the inner (upper) margin of the plate; the rest of the surface of 

 each superomarginal is covered by a fairly uniform but well-spaced 

 coat of low spinelets or spiniform granules, longest and most numerous 

 along the lateral margins of the plates. Terminal plate moderately 

 large ; it has all its spinelets rubbed off in the only instance where 

 the plate itself is not missing. 



Inferomarginals almost exactly like the superomarginals in all 

 particulars, except that the large spinelets are rather longer, and the 

 second spinelet on tlie inner edge of the interradial plates is larger 

 and so is quite conspicuous. The two series of marginal plates form 

 a vertical wall for each side of the ray, about equally in evidence 

 above and below; the fasciolar channels between the plates are 

 moderately developed more particularly in the interradii. Actinal 

 intermediate plates wanting at tip of ray and indeed on the entire 

 distal half; the first one adjoins the sixth inferomarginal (counting 

 from interradial line) and there are rather more than a dozen, lying 

 next to the adambulacrals, between that point and the oral plate : 

 a second series begins at the fourth marginal and contains nine or 

 ten plates; some 25-30 smaller plates fill up, more or less irregu- 

 larly, the remainder of the notably small actinal interradial area; 

 all the intermediate plates are covered, but not very thickly, with 



