NO. 5 CLARK: ECHINI OF WARMER EASTERN PACIFIC 233 



Hesperocidaris asteriscus-, new species 

 Plate 36, Fig. 4; Plate 37, Figs. 5-6 



Test somewhat flattened; vertical diameter about .60 of horizontal; 

 coronal plates 6; areolae large, occupying most of plate surface; median 

 interambulacral area narrow and fully covered with tubercles, smallest 

 next to vertical suture which is quite indistinct; ambulacra about one-third 

 of interambulacra in width ; poriferous zones rather wide and hardly at all 

 sunken ; median ambulacral area narrow with a single row of relatively 

 large tubercles on each margin and between these an irregular double series 

 of much smaller tubercles which become more and more scattered and 

 disappear entirely before the ocular plate is reached ; pores rather large, 

 horizontal or slightly oblique, nearly circular. Abactinal system about .50 

 h. d., rounded pentagonal, clearly defined, the anal area somewhat ele- 

 vated; each of the component plates and the anal area covered (save on 

 the margins) with flat spinelets, the larger ones on the anal system with 

 truncate or rounded tips, the others quite acute; the genital plates carry 

 30-35 spine-bearing tubercles, the ocular plates about 20; genital plates 

 distinctly longer than wide and much wider at the inner end than at the 

 slightly convex outer end ; ocular plates triangular, twice as wide as long, 

 the margins slightly convex; both genital and ocular plates are bare, 

 smooth and cinnamon color^ on the margins (excepting the distal margins 

 of the oculars) so that the genital plates form a conspicuous star-shaped 

 figure ; ocular plates all markedly excluded from the relatively large pen- 

 tagonal anal system. Actinostome rather large, more than .40 h. d., not 

 noticeably sunken, well covered with rather stout plates, which are hidden 

 by the numerous spines they carry; these spines are long and narrow, with 

 the distal end widened, rounded and curved inward very slightly. Primary 

 spines longer than horizontal diameter of test, nearly cylindrical, fairly 

 stout and blunt; they are densely covered with low, blunt tubercles in 

 about a dozen more or less regular longitudinal series ; collar veiy narrow; 

 secondary spines flat, only a little wider near the base than at the truncate 

 slightly rounded tip ; miliary spines, few, very small, acute. No globiferous 

 pedicellariae were found on any one of the specimens ; tridentate of two 

 kinds, one with long narrow jaws, are abundant. In color, the test is 

 pinkish cinnamon with the median ambulacral area distinctly light yellow- 

 ish olive ; secondary and miliary spines brownish olive of diverse shades ; 

 young primaries Japan rose or slightly darker, in some cases with one or 



2 asieriscus^a little star, in reference to the star-like figure formed by the 

 genital plates. 



3 Color names are from Ridgway Color Chart as determined at the time of this 

 study. 



