ASTEROIDEA DREDGED DURING CRUISE OF H.M.S. "TRITON." 155 



Station 11. August 28, 1882. Lat. 59° 29' N., long. 7° 13' W. 

 Depth, 555 fathoms; bottom temperature, 45 0, 5 Fahr. 



The propriety of retaining this form in the genus Astropecten appears to be 

 questionable. I propose to reserve the discussion of the subject until dealing 

 with some allied forms obtained by the " Challenger " expedition. 



6. Luidia ciliaris, Philippi. 



Station 3. August 8, 1882. Lat. 69° 39' 30" N., long. 90° 6' W. 

 Depth, 87 fathoms; bottom temperature, 49° 5 Fahr. 



I consider this form separate from L. Sarsii, D. and K. Both species were 

 comprised in Forbes' L. fragilissima. I regard L. Savignyi, Audouin, distinct 

 from either. 



Rhegaster, gen. nov. 



Marginal contour subpentagonal ; rays slightly produced. Abactinal sur- 

 face more or less convex, actinal flat. The whole body covered with mem- 

 brane, beset with crowded spinelets. 



Abactinal skeleton composed of irregular plates, crowded and subimbricated 

 in places, which leave small irregularly disposed meshes. The whole skeleton 

 is hidden in a thick membrane, and furnished with a compact covering of 

 small, uniform, crowded spinelets. Papulae small, numerous, isolated, irregu- 

 larly distributed over the whole area. Infero-marginal plates large, forming 

 the margin of the test. Supero-marginal plates superficially invisible, concealed 

 in the dorsal membrane. Actinal interradial areas with large subregular plates, 

 hidden by a superficial membrane, with small crowded spinelets. 



Adambulacral plates broader than long. Ambulacral spines short and 

 thickly invested with membrane, forming a regular furrow-series and several 

 subregular longitudinal rows externally. Ambulacral sucker-feet in simple pairs, 

 with small sucker-disk. 



Madreporiform body small, midway between margin and apex. Anus sub- 

 central. No peclicellarige. 



This genus comes within the scope of the family Asterinidce as defined by 

 Dr Viguier, and appears to be well distinguished from the other genera of the 

 group. In addition to the species now described, I include in the genus the 

 interesting form named by Dr Stuxberg* Solaster tumidus, but which has more 

 recently been referred to the genus Asterina by Drs Danielssen and KoREN.t 

 The latter naturalists have given an admirable description, and two detail 



* Ofversigt af Kongl. Vet.-Akad. Forhandl, Arg. 35, 1878 (1879), No. 3, p. 31, pi. vi. 

 f Nyt Mag. f. Naturvidensk., Bd. xxvi. hffc. 2, p. 182, pis. i. and ii. figs. 6-10. 



