SEA LILIES, STAKFISHES, ETC. — CLAEK. 55 



are evident, especially on the sides of the arms. The super- 

 ficial appearance of alcoholic specimens of Pseudophidiaster is 

 more like that of Phataria than like that of Ophidiaster, but 

 the latter genus seems to be structurally more nearly allied. 



Pseudophidiaster rhystjs,i sp. nov. 



(Plate xvi., fig. 1-2.) 



R = 150mm. ; r=25 mm. ; R=6r. Br=27 mm. ; R=not 

 quite 6 br. Br at middle of ray, about 15 mm. ; at tip, 3-4 

 mm. Disk large, considerably elevated, the median radial 

 series of plates extending outward from it in equally elevated 

 ridges ; rays therefore more or less distinctly trigonal at base, 

 but tapering quite uniformly to a cyHndrical, bluntly pointed 

 tip. Whole animal clothed in a thick skin, bearing a dense 

 coat of crowded granules, and conceahng almost completely 

 the skeletal plates ; on papular areas, there are 60 or more 

 granules per square millimeter, but on convexities and eleva- 

 tions of disk and base of rays, the granulation is mvich coarser, 

 sometimes only 4-10 per square millimeter. Median radial 

 series of abactinal plates very conspicuous proximally, but 

 becoming less and less distinct distally ; on each side is a much 

 smaller series which, beyond the middle of the arm, becomes 

 irregular and difficult to distinguish ; then comes the series 

 of superomarginals which are quite well marked except near 

 tip of ray ; inferomarginals as large or larger, and generally 

 easily followed to very tip of ray, since they form the ventro- 

 lateral margin of the arm. Papular areas rather small, each 

 with 20-25 papulae, forming eight regular series, one on each 

 side of arm being actinal in position, below the inferomarginal 

 plates ; distally the series are less regular and the actinal do 

 not reach the tip of the arm. Madreporite very large and 

 conspicuous, 10 mm. long by 8 mm. wide. Terminal plate 

 very small and inconspicuous. 



Actinolateral plates in three regular series proximally, with 

 a few plates indicative of a fourth series ; the third series 

 disappears about one-third of the distance from mouth to 

 arm tip ; the second extends beyond the middle of the arm ; 

 the series adjoining the adambulacrals apparently extends 

 nearly to the arm tip. Adambulacral armature of 2 flattened, 

 smooth spines nearly 2 mm. long, with blunt, rounded tips, 

 placed close together, the aboral the slightly smaller of 



1. ^i;ffo9= wrinkled, shrivelled ; in reference to the appearance of dry- 

 specimens. 



