356 CLARK. 



mm.), but only the two longest have normal tips; the next two have 

 the tips .truncate and the shortest has the tip conspicuously regener- 

 ated, the new part being 7 mm. long; all the rays are flattened cylindri- 

 cal, slightly constricted at base; only the terminal fourth tapers to 

 the normally pointed tip. Body surface very finely and uniformly 

 granular, 80 or more granules to a square millimeter in the dry con- 

 dition. Papulae in 8 well-marked series of large, scarcely depressed 

 areas, 20-50 to each area, except near base and tip of arm, and on 

 disk, where areas are evidently smaller; papulae of actinal areas appear 

 to be a little larger than those of abactinal surface; on basal part of 

 arm each area is very much larger than any adjoining plates, a typical 

 one being 2 mm. long and 4 mm. wide; series of areas fairly regular 

 and parallel till very near arm-tip where they converge and each area 

 is greatly reduced containing only one or two papulae. Marginal 

 plates not noticeably larger than, nor different from, abactinal plates. 

 Terminal plate relatively small, not much more than 2 mm. across, 

 not granular but with about 7 fairly large tubercles. Madreporite 

 smooth, flat, 3 mm. across. 



Pedicellariae numerous but widely scattered abactinally, not on 

 the plates but on the papular areas with seldom more than one to an 

 area; the valves and sockets are straight and narrow; each valve is 

 about 0.3-0.4 mm. long, markedly compressed, straight, terminating 

 in a sharp tooth nearly at a right angle to the valve itself; below this 

 terminal tooth are three or four much smaller and stouter, blunter 

 teeth; the sides of the socket are somewhat irregularly serrate in the 

 dry condition but carry no real teeth. Actinally there are several 

 pedicellariae on the interradial areas and here and there on a papular 

 area on the rays, but the characteristic feature of the species is the 

 series of pedicellariae that lie on the adambulacral plates between the 

 furrow spines and the subambulacral spines; these pedicellariae are 

 somewhat larger than those of the abactinal surface but are otherwise 

 like them; for the most part they lie end to end in a single almost 

 continuous series placed on a fleshy ridge or fold of skin close to the 

 subambulacral spines, but there are many scattered pedicellariae 

 also, usually lying at more or less of an angle to the ridge or squarely 

 across it, and in many places the ridge disappears or is very indistinct; 

 there is no ridge and there are few pedicellariae on the distal third of 

 the ray. 



Adambulacral armature as usual in two series; furrow spines in 

 pairs, subequal, about three or four times as long as wide and about 

 once and a half as wide as thick, with slightly rounded tips, con- 



