PONTASTER. 61 



Ziitk. Vid. Medd. 1871 (1872), p. 240 ; Moeb. $ Bidschli, JB. Comm. 



Kiel, ii. & iii. (1875) p. 148 ; Perr. Arch. Zool. v. (1876) p. 268 ; 



Kor. Sf- Dan. Nyt May. xxiii. (1877) 3. p. 59 ; iid. Norske Nordhavs 



Asteroidea, (1884) p. 85. 

 Pontaster tenuispinus, Slade?i, Chall. Rep. Ast. (1889) p. 28. 

 Pontaster tenuispinis, Bell, Ann. fy Mag. iv. (1889) p. 433 ; id. P. Z. S. 



1892, p. 430, pi. xxvi. 

 Pontaster tenuispinus, var. platynota, Sladen, Chall. Rep. Ast. (1889) 



p. 29. 

 Pontaster hebitus, id. op. cit. p. 33. 

 Pontaster limbatus, id. op. cit. p. 35. 



The proportion of E to r of disk varies between 3| and 7f ; a 

 very variable species in many characters. 



Disk and arms flat, but the depth of the side at the angle of the 

 disk varies somewhat ; the arms taper regularly and, as a rule, end 

 in fine points. The bases of the arms on the dorsal surface some- 

 times, but not always, marked by a perforated area (the " papu- 

 larium"), of an elongate lens-like form containing from about ten 

 to twenty holes. The sides of the arms, above, bounded by a pretty 

 stout superomarginal, which may, however, be so thin as to be 

 merely a line on the upper surface. There may be as many as 40 

 superomarginals, and pretty constantly each carries a well-developed 

 spine, the base of which is surrounded by a number of spinelets. 

 A similar, or sometimes rather stouter, spine is borne by each infero- 

 marginal, and one or more of the surrounding spinelets may be 

 prominent on account of their length. The intermediate plates on 

 the lower surface are, as a rule, thickly covered with spines, but in 

 these last there are, at times, reductions. The spines on the anibu- 

 lacral plates vary considerably in number and disposition, but the 

 most usual arrangement appears to be a row of about six small 

 sipnes along the groove, with one, two, or three larger spines set 

 transversely. Pedicellaria? present or absent. Delicate spines may 

 sometimes be seen rising from the dorsal paxilliform plates. 



R = 10; 10; 11-5; 13; 14; 14; 16-5; 18. 

 r = 74 ; 47 ; 55 : 49 ; 64 ; 72 ; 66 ; 61. 



Distribution. Both sides of North Atlantic, as far south as 

 Scilly Islands ; Arctic Ocean, Kara Sea. 70 to 778 fms. 



a. Faeroe Channel, 365 fms. ' Porcupine ' Exp. (St. 65). 



b, c. Faeroe Channel, 363 fms. 'Porcupine' Exp. (St. 54). 



d-f. Faeroe Channel, 540 fms. ' Knight Errant ' Exp. (St. 8). 



y-i. Faeroe Channel, 608 fins. ' Triton ' Exp. (St. 9). 



A: Faeroe Channel, 305 fms. ' Porcupine ' Exp. 



Z-p. Off Valentia, 100-150 fms. ' Porcupine ' Exp. 



q-io. S.W. coast of Ireland, 315 fms. ' Flying Fox' Exp. 



x-z. S.W. coast of Ireland, ? 250 fms. ' Flying Fox ' Exp. 



a'-d'. S.W. coast of Ireland, 90-400 fms. G. C. Bourne, Esq. 



e'-h'. S.W. of Scilly Islands, 305 fms. ' Porcupine ' Exp. 



