PKOCEEDIXaS OF THE NATIONAL MUSEUM. 247 



to four-valved, or pectinate. Superambulacral plates are lacking. 

 Fascioles rudimentary or lacking. 



PONTASTER HEBITUS, S 1 a d .■, ii . 



rontaster hebitus, Sladkn, Voyage of the Cliallenner, x\x, p. 3H. ])1. 8, fio.s. 1, 2; 



pi. 12, tigs. 1, 2, 1889. 

 Archasia'ienuisphiHS, Yy^hhill, Proc. U. S. Nat. Mus., ii, p. 203, 1879; Rep. Com'r 



of Fi.sli aud Fisheries, xi [for 1883], p. 543, pi. 13. fig. 38, 1885 (probably not 



of Diiben and Koren). 



In my former papers 1 considered this species identical with P. 

 teHuispinus of northern Europe, but Mr. Sladen describes it as distinct. 

 The two forms are certainly very closely related, but, as I lia ve not had 

 the P^uropean species for comparison, I follow his decision. 



Our specimens, however, in many cases, approach nearer to the Eu- 

 ropean form than does the type of P. hehitus, as described by Sladen ; 

 for in our series the marginal and adambulacral spines are often mostly 

 long and acute (not truncate as described) and the disk is often as large 

 as in P. tenuispinus. But the i)edicellaria\ characteristic of the latter, 

 seem to be absent in the American form. 



Most of the specimens have been taken by the Gloucester, Mass., 

 fishermen from the fishing l)anks off IS^ova Scotia and Newfoundland, 

 in 128 to 2r>0 fathoms. 



PONTASTER FORCIPATUS, S 1 a d (; ii . 



I'inilaster /orcipatit.H, Si.adkn, Voya.ne of th<! ChaUcujier, xxx, p. 43, pi. 8, figs. 3, 



4; pi. 12, figs. 3, 4, 1889. 

 Archasier tcnuisjylnus, Verrill (part), op. (it., xi, p, 543, 1885 (not Dub. and Koren). 



This species was also included by me, in some of my former articles, 

 under the name of Archasier teiiuisiyinxs, of which it was at first sup- 

 l)osed to be a variety. 



It is easily distinguished from P. hebitus by the presence of only a 

 single large spine on the actinal surface of the adambulacral plates. 

 The peculiar four-valved to six-valved pedicellari;e are usually present 

 in considerable numbers on the ventral surfaces; sometimes, on the dis- 

 tal part of the ray, pedicelled, three- valved ones occur. The central 

 spine of the dorsal plates is larger and longer than in P. hehitus, and so 

 are the marginal si)ines of both series. The papular areas are smaller, 

 more rounded, and have but few pores. This species was taken at 

 many stations, in depths ranging from 956 to 1,396 fathoms. 



PONTASTER SEPITF.S, \' e r r i 1 1 . 



Archatster sepiius, ^'EHR1LL, Anier. .Jonrii. Science, xxix, p. 151, Feb., 1885. 



This species is a true Pontaster. It is very distinct from both the 

 preceding, and is easily distinguished by the relatively larger, broader, 

 thicker, and more convex marginal plates, with deeper sutures between 

 them. The marginal spines are more conical, with enlarged bases, but 

 not so long as in the last species. The dorsal spinopaxilke and para- 



