ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS FISHER. 361 



Actinolateral spines very short, the proximal ones only one and a half to one 

 and throe-quarters times as long as outer adamhiilacral spine; eonsequentlv, the 

 membrane is narrow and does not increase very mueli in width proximally. In 

 larfje specimens this membrane is flush with the peneral actinal floor, there being 

 no free edge or fringe except far along ray. In young examples and in dried spec- 

 imens there is always a more or less marked free border to the actinolateral mem- 

 brane. 



Color in life, variable, generally blui.sh gray or dull purplish mottled with fawn 

 color; a specimen from station 42^5 was very light yellowish (yellowish white) in 

 life, the tube feet canary yellow. The mottling usually persists in alcohol. 



Anatomical notes. — Abactinal plates cruciform with four (or five) long slender 

 truncate lobes. Madreporic body very convex, as high as wide, with a tuft of 

 spines at the top ("pseudoplacote"). Anal opening very large, surrounded by a 

 membranous periproct 1 1 mm. broad, and bounded by the five large radial (osculum) 

 paxillas. Anus opens from a spacious simple chamber with four short saccular 

 diverticula. This chamber in turn connects with the dorsal stomach by a large 

 aperture. Hepatic cceca large. Very strong muscles from the enlarge<l first 

 ambulacral ossicle to stomach wall. Gonads interratlial, in large tuft. Apparently 

 no Polian vesicles; Tiedemann bodies large. First tube feet, on either side, with 

 only one ampulla (as in Pt. jordani); the rest with two. Interradial septa mem- 

 branous, tough. 



Variations. — The Alaskan and British Columbian specimens vary slightly in 

 proportions, some having more inflated and shorter raj's than others. The tip of 

 the ray is more or less upturned or reflected, so that the ends of the ambulacra 

 assume a dorsal position. The degree of this upturning causes a variation in the 

 length of rays; the extremes are about R=1.5 to 1.S5 r; those less than 1.6 r are 

 young; the usual is R = about 1.65 r. Besides a variation in color there is also a 

 great difference in the texture of the supradorsal membrane. Usually it is only 

 slightly roughened by the tips of tiie spinelets. The reticulation shows most plainly 

 on the lat<»ral and ventrolateral surfaces, and oft-en not at all plainly on tiie dorsal 

 surface. If the surface laj'cr of the supradorsal membrane is much swollen, the 

 reticulations are wholly or parth* obhterated and the spiracula appear to open into 

 fine furrows or creases. Variations in the adambulacral spines and actinolateral 

 membrane have already been alluded to. 



Type. — No. 202, Academy of Natural Sciences, Philadelphia. 



Type-hcality. — Kadiak Island, Alaska. The locality was omitted in the 

 original description, but was recorded later." 



Distribution. — Bering Sea (Bering Island, Pribilofs, Ilagemeister Island) south 

 along the North American coast to Washington. 



oProc. Acad. Nat. Sri. Phila., 1889, p. 175. 



