300 BULLETIN OF THE BUREAU OF FISHERIES. 



Madreporic body convex, prominent, circular, with coarse, irregular centrifugal striations; situated 

 about J its own diameter from the edge of the iuterradial plate. 



Locality: Station 4387, off San Diego, Cal. (longitude of Point Conception), 1,059 fms., mud. 



This species is provided with pedicellarise on the proximal 2 or :•> inferomarginal plates, and 

 abundantly on the abactinal surface. In Sladen's synopsis of Pararchasler (Challenger Asteroidea, 5) 

 the present form would be arranged under I>, section a, where also P. huddlestoni and /'. viotoceus of 

 Aleock apparently belong, acanthonotus, in respect to the inferomarginal pedicellarise, being nearer 

 the latter form. From this it at once differs in having a profusion of abactinal pedicellarise, slenderer 

 and smoother marginal spines, a less prominent inferior iuterradial marginal plate, and a different 

 adambulacral and dental armature. The present species is nearest pedicifer, among those described by 

 Sladen, bul really docs not bear comparison with that form. 



Family PLUTONASTERID^ (Sladen) Yen ill, 1899. 



Genus DYTASTER Sladen. 

 Dytaster Slarlen, Narr. Challenger Exp., 1, (Ms, 1885. 



Dytaster gilberti, new species. 



Kays 5. R = 114mm.; r = 22 nun. R = .").L> r. Breadth of ray at base, 22 mm.; at tenth super- 

 marginal, J length of ray, 17."i mm. 



Rays elongate, robust, tapering at first very slightly, then more rapidly, to a pointed extremity: 

 abactinal integument inflated on disk, plane on rays; actinal surface convex; lateral wall of ray vertical 

 on proximal half, gradually arching inward and upward on outer half, so that the marginal plates 

 form a steep bevel; interbrachial arcs rounded. 



Abactinal paxillar area covered with small paxillae without definite order, and rather crowded 

 on disk but distinctly spaced on ray; each consisting of a short pedicel surmounted by short, cylindri- 

 cal, papilliform, obtusely-tipped, equal-sized spinelets, or the peripheral slightly slenderer; 15 to L'o 

 in number al base of rays, even more on disk, and about 12 to 15 at outer part of ray. These 

 stand vertically, the peripheral series flaring a trifle on disk and basal portion of rays, but all 

 radiate on paxillse of the outer part of ray. Over most of the ray papulae may be distinguished 

 between paxillse. 



Supermarginal plates, 50 in number from median iuterradial line to extremity of ray, nearly 

 quadrate except in interbrachial arc, where they are higher than long; plates confined to side wall, 

 except that the upper end forms a very narrow bonier to the paxillar area; each plate slightly tumid 

 and bearing a rigid, erect, robust, tapering spine at the abactinal end, about as long as height of plate; 

 general surface of plates covered with very small papilliform spinelets which are slenderer at the 

 edges than in the center; inferomarginals corresponding, plate for plate, with superomarginals, tumid, 

 forming a rounded border to actinal area, and covered, like the dorsal series, with a line nap-like 

 spinulation, which is coarser and more widely spaced on the actinal surface; in center of each plate a 

 tapering, rigid spine, which stands out at right angles to lateral wall of ray, and is a trifle longer than 

 corresponding dorsal marginal spine; these L' series very regular and extending the length of the ray 

 the lower on the line between the actinal and lateral faces; on the first - superomarginals an 

 additional spine between regular spine and actinal margin of plate. , 



Adambulacral plates longer than wide, with a slightly curved farrow margin; armature consisting 

 of (1) a furrow series of 10 (8 or !i sometimes) fragile, slightly tapering, round-tipped, faintly com- 

 pressed spinelets, which are slightly bent at the base and graduated toward either end of the series; 

 I 'J 1 on the actinal surface just behind the furrow series, a longitudinal row of about much shorter, 

 thick, clavate spinelets, and on the outer edge of the plate a series of delicate, slender, tapering, 

 papilliform spinelets which follow the contour of the plate and are smaller than the other series; 

 furrow spinelets about as long as extreme width of plate. 



Mouth plates huge, prominent actinally, and the united pair broadest at middle, but only slightly, 

 or not at all, narrower at outer end; lateral margins toward furrow slightly excavated, and the end 

 toward actinostome truncate. ( Unfortunately the armature in the specimen examined has been 

 largely destroyed.) Marginal series much like that of adambulacral plates, and consisting of about 

 14 spines, compressed and curiously expanded above the slender base, from this expansion tapering 



