1894. 



PROCEEDINGS OF THE NATIONAL MUSEUM. 249 



This species has distinct though short superambulacral plates at the 

 base of the rays and within the margin of the disk, but they are lack- 

 ing iu the distal jmrt of the rays. The papuloe are confined to a star- 

 shaped area, occupying the center of the disk and the basal median 

 part of the rays. 



A few regular six-rayed specimens were taken by the Albatross . 



The young, when very small, differ greatly from the adults in 

 structure and appearance. 



This is one of the most abundant of the deep-sea starfishes taken 

 by the U. S. Fish Commission, as well as one of the most beautiful. 



It occurred at many stations in 182 to 1,594 fathoms. 



This and the other species of Flutonaster would be included in the 

 genus Goniopecten, as defined by Perrier, but as his first species {G. 

 demo list rans) appears to be a distinct generic type, perhaps allied more 

 nearly to Psilaster, and apparently belonging to the Astropectinidte, his 

 name should be restricted to that type. 



Subfamily P«eudarciiasterin^, S laden. 



PSEUDARCHASTER INTERMEDIUS, S 1 a d e n . 



Pseud arch aster inter medius, Sladex, Voyage of the Challenger, xxx, p. 115, pi. 19, 



figs. 3, 4 ; pi. 42, figs. 5, 6, 1889. 

 Archaster parelii, Verrill, Amer. Jouin. Science, vii, p. 500, 1874 (not Diibeii and 



Keren); xxiii, p. 140, 1882; Rep. U. S. Com'r Fish and Fisheries, xi, p.543, 



pi. 13, fig. 37, 1885 (var. with narrow rays). 



According to Sladen, this is distinct from the allied European imrelii-, 

 with which I formerly identified it, but without a direct comparison 

 of specimens. 



Our numerous specimens show considerable \ariation, esi)ecially in 

 the size of the marginal plates as compared with the breadth of the 

 dorsal area of the rays. In some examples the upper marginal j)lates 

 are so broad that the dorsal area is much reduced in breadtli. In 

 others the marginal plates are comparatively narrow, while the dorsal 

 area is wider. 



These differences are not correlated with any others of importance, 

 so that they can hardly be taken as characteristic of permanent vari- 

 eties. 



The papulae are confined to the central part of the disk and baso- 

 median part of the rays. 



Distinct fascioles are present in our specinaens between the plates 

 next to the adambulacral series, as in P. discus, but Sladen states that 

 they are wanting in his examples. Moreover, in all our specimens there 

 is a median row of several enlarged spinules decidedly larger than the 

 rest, on each of the inferior marginal plates, which was not the case in 

 Sladen's specimens. Similar enlarged spinules occur on most of the 

 actinal interradial plates. In consequence of these differences our 

 examples approach much nearer to P. (Zisc?/s Sladen, from the west coast 



