British Species allied thereto. 477 



arms, varying somewhat in the number to which they are 

 developed. 



Colour, Red, orange, or purple. 



Distribution. Eastern side of North Atlantic (Senegal to 

 Finmark) ; Japanese Seas. Presence in Arctic Ocean 

 uncertain, in Mediterranean very doubtful. 



A. rubens, var. attenuata. 



A. rubens, var. attenuata, Hodsie, Trans. Northumb. and Durham, iv. 

 (1872), p. 137. 



Varieties with very slender arms and rare spines are some- 

 times so well marked that, as I have already indicated, I am 

 inclined to think we may mark the variation by a name. 

 Mr. Murray dredged such a specimen off Tobermory, Mull 

 (30 fath.), and one of the ' Knight Errant' forms dredged off 

 North Rona and described by Mr. Sladen may be put in the 

 same category. 



R = 105; 75: r = 15; 13. 



Breadth of arm at base 14 ; 15. 



Miiller and Troschel accepted the statements of Lamarck 

 and Risso as to the presence of A. rubens in the Mediterra- 

 nean ; Prof. Perrier in 1875 spoke of it as " provenant de 

 toutes les mers de I'Europe," and in 1884 Messrs. Koren and 

 Danielssen practically say the same thing ; but in 1878 

 Perrier wrote that it ^'ne parait pas penetrer dans notre grande 

 mer interieure ; " it is not given by Professors Sars or Ludwig 

 in their reports on the marine fauna of the Mediterranean, 

 and Cams accepts Perrier's later view. 



With regard to the presence of A. rubens in the Japanese 

 Seas it is customary [cf. Perrier or Koren and Danielssen) to 

 make Dr. v. Martens responsible for the statement that the 

 species is found there ; but v. Martens refers to specimens 

 from Japan seen and recorded by Miiller and Troschel. 

 Perrier adds, " Jusqu'ici aucun autre fait n'est venu confirmer 

 cette afBrniation." Almost contemporaneously, however, Mr. 

 Sladen recorded A. rubens^ var. migratum^ from the Korean 

 Straits*. 



The question arises therefore as to the circumpolar distri- 

 bution of the species ; Wagner and Jarzynsky report it from 

 tlie White Sea, but it is not to be found in Levinsen's list of 

 Echinodevms from the Kara Sea ; Sabine reports it from 

 Davis Strait, but Duncan and Sladen do not give it among 

 the Greenland Echinoderms. On this point it seems to be 



* I cannot find any reference to this form in Mr. Sladen's ' Challenger ' 

 Report. 



