94 ASTER0TDE4. 



2. Pteraster personatus. 



Pteraster personatus, Sladen, Proc. P. Irish Acad. i. (1891) p. 694, 

 pi. xxviii. 



It = 70; r = 25milJim. 



This species is stated to have the facies of Hymenaster and to be 

 intermediate in many respects between Pteraster and Hymenaster. 

 The comb of adambulacral spines forms a regular semicircular 

 curve and is curved round aboraliy at the margin of the furrow. 

 There are no secondary or superficial spines on the actinal surface 

 of the mouth-plates. 



Found at 51° 1' N., 11° 50' W. 750 fms. 



2. HYMENASTER. 



Hymenaster, Wi;v. Thorns. Depths of the Sea, (1873) p. 120; Dan. §■ 

 Kor. NorsJce Nordh. Ast. (1884) p. 79 : Sladen, Chall. Pep. Ast. (1889) 

 p. 470. 



A Pterasterid in which there are no transverse adambulacral 

 combs of spines and no web ; the marsupial cavity is spacious. 

 The well-developed supradorsal membrane contains muscular fibres. 

 Spiracula present. Spinelets of paxilhe short, and not protruding 

 through the membrane. 



1. Hymenaster pellucidus. 



Hymenaster pellucid us, Wyv. Thorns. Depths of the Sea, (1873) p. 120, 

 "tig. 16; Dan. $ Kor. Nyt May. 1877, p. 68_, pi. iv. figs. 1-14; 

 iid. Norske Nordhavs Ast. (1884) p. 72, pi. xiii. figs. 1-17, pi. xv. 

 figs. 7 & 8 ; Slad. Chall. Pep. Ast. (1889) p, 508. 



R=2 r. 



Abactinal surface arching towards the centre, actinal surface flat. 

 Five large paxillse round the funnel-shaped aperture of the marsu- 

 piurn, each of which carries six to eight short and eight to ten long 

 calcareous needles ; the remaining paxilhe have four long and 

 three short needles. Each adambulacral plate has three spines, two 

 of which face inwards, while the third faces the semilunar aperture 

 on the lateral margin of the ray. Madreporite circular. 



Colour very red ; integument translucent. 



Distribution. Eastern side of North Atlantic as far as Jan Mayen 

 and Spitsbergen. 70 to 1539 fms. 



a. Faeroe Channel, 580 fms. ; Porcupine ' Exp. (St. 59). 



Specimens from 12 to 80 millim. in diameter have been examined 

 by Messrs. Koren and Danielssen, from whose diagnosis that just 

 given has been drawn up. 



