318 



BULLETIN 76, UNITED STATES NATIONAL MUSEUM. 



in extreme examples are closer together, and both series have more spinelets, 

 which may or may not be shorter than in specimens from 3331. In the variety, 

 also, the actinal spinelets are more heavily invested with membrane and the 

 actinal adambulacral spines are more numerous (eight or nine proximally). The 

 suboral spinelets form a dense cluster on each plate. In extreme cases the actinal 

 interradial area is smaller (pi. 89, fig. 2), with relatively larger and fewer paxillse. The 

 general appearance of the actinal surface is that of more dense spinulatiou and 

 more compact marginals. The specimen from 2853 (pi. 89, fig. 1 ), however, although 

 typical of this variety abactinally, has an actinal surface similar to specimens from 

 3331, and thus combines characters of each form. The specimens from 3500 also 

 belong to both forms. The superomarginal paxillse present gradations between the 

 two extremes. 



The specimen from 4784 is an extreme example of the variety with unusually 

 large superomarginals. It resembles aberrant specimens of S. dawsoni, but is 

 probably referable to paxiUatus as the actinal combs of adambulacral spines are 

 curved, not straight, as in dawsoni. 



It is certainly very tempting to consider this variety a distinct species, but the 

 evidence of intergradation can not be ignored. There is a possibility that the 

 variety is really a northern form, which is hybridizing with true jjaxillatus, derived 

 from the south. 



Ti/pe.— British Museum. 



Type-locality. — South of Yokohama, Japan, CJiaUenger station 232, 345 fathoms, 

 green mud. 



Distribution. — From south of Yokohama, Japan, to Bering Sea, thence to 

 vicinity of Kadiak Island, Alaska, 56 to 350 fathoms; the typical form in deeper 

 water. 



Specimens exumincd. — Twenty-two, from the following localities: 



Specimens of Solaster paxiUatus examined. 



2853 

 3223 

 3331 

 3500 

 3608 



4784, 

 4792 



South of Kadiak Island, Alaska 



on Unlmak Island, Alaska 



North of Unalaska 



South of St. George Island, Bering Sea 

 Bering Sea, between St. George and 

 Unalaska. 



Near Attu Island, .\laska 



Off Conunander Islands 



Nature of botto 



gray sand 



black pebbles. 



mud 



fine gray sand 

 gray sand 



coarse pebbles 

 pebbles 



U. S. Nat. Mus. 



Remarks. — This species differs from dawsoni in having more prominent and 

 typically more widely separated inferomargmals, and in having the superomarginals 

 alternating with the uiferomargmals. The actinal interradial areas are much 

 larger than m dawsoni, and the actinal comb of adambulacral spines is curved at 

 the inner end, while in dawsoni it is nearly or quite straight. 



From S. horealis, paxiUatus differs in having much larger abactinal paxillse, ui 

 lacking the bare interradial streak, in having more numerous inferomarginals, with 



