JAPANESE ASTEROIDEA. 



385 



der Besclireibung vereinbaren, die Danielssen und Koken (1876, 1884) von 

 Plutonaster jpareUi var. longobracJdalis geben." 



Grieg Las some remarks on this species under the name of Plufonasfer 

 parelii [ ; 02, p. 19] : 



" Findested : Svserholt 2 eksem- 

 plarer, Foldenf jord 530 m. 1 eksem- 

 j)lar, Svolvger 1 eksemplar og Balstad 

 150 m., 1 eksemplar. 

 Skiveradius 10 mm. 7 mm. 5 mm. 



5 mm. 



Ai-mradius 28 mm. 18.5 mm. 14 mm. 



10 mm. 

 Antal randplader 48 30 26 24. 



" Skiven er saaledes forholdsvis 

 st0rre hos de yngere individer, 1 : 2 

 mod 1 : 2.8 hos det st0rste. Doder- 

 LEIN paa viser, at den relative Isengde 

 af armene hos en del arktiske asteri- 

 der er underkastede store variationer, 

 hvorfor dette merke ikke som hidtil 

 b 0r benyttes som artsmerke. Denne 

 tilbçiiehghed til at variere gjaelder 

 ikke alene de af Doderlein nsevnte 

 arter, jeg har ogsaa fundet de thos 

 plutcnaster parelii, leptoptychaster 

 articus, psilaster andromccJa, o. s. v. Paa 

 en af de meUemste dorsale randplader 

 hos eksemplaret fra Balstad fandt 

 jeg en st0rre pig, der ganske hgner 

 den, der sidder paa de ventrale 

 randplader. 



" Ai-ten er udbredt längs hele 

 vor kj'st, men er overalt sjelden. 

 En eiendommeh'g langarmet varietet 

 fand Nordhavsekspeditionen i Tana- 

 fjorden." 



Locality : Svserholt 2 exam- 

 ples, Foldenf jord 530 m. 1 example, 

 Svolvaer 1 example and Balstad 

 150 m., 1 example. 

 Disk radius 10 mm. 7 mm. 5 mm. 



5 mm. 

 Arm radius 28 mm. 18-5 mm. 14 mm. 



10 mm. 

 IS^umber marginal plates 48 30 26 24. 



The disk is thus relatively 

 larger in the younger individuals, 

 1 : 2 against 1 : 2-8 in the largest. 

 Doderlein indicates, that the relative 

 length of the arms in some arctic 

 starfishes is subject to great varia- 

 tions, on which account this character 

 should not be used as a specific charac- 

 ter as heretofore. Tliis tendency to 

 vary concerns not only the species 

 mentioned by Doderlein, but I have 

 also found it in Plvionaster parelii^ 

 Leptopty chaster ardicns, Psilaster an- 

 drcmeda, etc. On one of the inner- 

 most dorsal marginal i^lates of the 

 example from Balsted I found a 

 larger spine, quite similar to that 

 which occurs on the ventral mar- 

 ginal plates. 



The species is distributed along 

 our whole coast, but is everywhere 

 rare. A peculiar long armed variety 

 was found by the Noiih Sea Expedi- 

 tion in the Tanafjord. 



