SHALLOW-WATER STARFISHES 269 



The appressed retroambulacral or " actino-marginal " spines are 

 unusually short and stout, a little flattened and enlarged distally, 

 and almost twice as long as the adambulacrals ; but they do not reach 

 a third of the distance to the margin in the middle of the interradial 

 areas, so that the dorsal spinulation extends well onto the under side, 

 making the margins thick and swollen. They end at a strong, free 

 fold of the membrane, which only becomes marginal near the ends 

 of the rays. The peractinal spiracles or pores are narrow slits, with 

 narrow, elongated, somewhat crescent-shaped valves. Adoral spines 

 form about five graded pairs, completely webbed ; the terminal ones 

 are rather stout; the distal, very slender. Epiorals large, tapered, 

 translucent distally. The dorsal spiracles are small and numerous, 

 but in dry specimens and some alcoholics they are invisible, owing 

 to strong contraction. 



This species is known from Bering Sea to Puget Sound. My 

 specimens are from Yakutat (Professor Ritter) and Sitka (W. R. 

 Coe), Harriman Expedition; Puget Sound (Professor Kincaid) ; 

 off Sidney Islands, May 10, 1896 (Prov. Mus. B. C.) ; British Colum- 

 bia (Canada Geological Survey). Mr. Ives recorded it from Marmot 

 Island, Alaska (type locality). Fisher recorded it from Bering Sea, 

 off Pribilof Islands ; off Shumagin Islands ; off Unalaska, and various 

 other Alaskan localities, from low water to 150 fathoms; off Van- 

 couver Island, in 238 fathoms; Straits of Fuca, 114 fathoms; near 

 Port Townsend, 15 to 39 fathoms; etc. Some of his specimens were 

 much larger than the one described above. He gives the radii of one 

 specimen as 54 mm. and 88 mm. ; ratio, i : 1.63. 



PTERASTER TESSELATUS ARCUATUS Fisher. 

 Pteraster tesselatus arcuatus FISHER, op. cit, 19116, p. 363, pi. cm, fig. I. 



Similar to P. tesselatus, but arcuately pentagonal in form, with 

 thick supradorsal membrane, without signs of reticulation ; spiracula 

 sunken in irregular creases. Radii, 32 mm. and 46 mm.; ratio, 

 i : 1.44. 



Color in life, above, bluish gray or dull heliotrope purple, mottled 

 with fawn-color, with dark interradial and lighter radial areas, and 

 dark around margins ; interradial areas below, dull heliotrope purple ; 

 marginal membrane, vinaceous buff (teste Fisher). 



Monterey Bay, in 46 to 56 fathoms (Fisher). 



This appears to be the same as the next, grown to larger size. 



