34 ON THE ECHINODERMATA OF THE 



Variations. Much variation occurs in this species, as might naturally be expected 

 in an organism enjoying such a wide geographical range ; indeed some of the divergen- 

 cies are so well marked that they have from time to time been taken by several writers 

 as types of distinct species. Thus Echinaster Sarsii, M. & T., is in reality nothing more 

 than the young phase of our Greenland form, whilst its adult stage has served as the 

 type of Echinaster Eschrichtii, M. & T. (= Asterias pertusa, Miiller). Similarly Linckia 

 (Cribella) oculata, Forbes (the Asterias spongiosa of Gould), is the shorter-armed and 

 more densely spinulated variety of the species, and which inhabits, as a rule, the 

 southern portion of the area of distribution. All these forms, however, when studied 

 in series, are found to fall, by imperceptible gradations, into simple modifications of the 

 Starfish named by O. F. Miiller Asterias sanguinolenta, and earlier known to Linck as 

 Pentadactylosaster oculatus. 



Brandt, as well as Diiben and Koren, have already indicated the chief variations 

 that occur in this Starfish the former classifying them under the terms of varietas 

 macrodiscus and v. microdiscus, and the latter authors as forma major and forma minor 

 (vulgaris), each mentioning the main superficial characters that accompany the 

 lengthening and shortening of the ray. Brandt records the short-armed variety from 

 the west coast of the White Sea, and the long-armed one from the Ochhotsk Sea, near 

 Chantar Island. 



Distribution. 



a. Greenland: Hare Island, Waigat Strait, lat. 70 30' N., 175 fms. (' Valorous' 

 Exped.), the most northern locality on record ; Egedesminde, 50 fms. (Lutkeri). 



b. North of American Continent : Grand Manan (Stimpson) ; Massachusetts, 

 Maine, and east coast of N. America. 



c. North of European Continent : Spitzbergen (Lutken) ; Iceland, Fa3roe Islands, 

 Scandinavia, and British coasts as far south as the English Channel ; White Sea 

 (Brandt). 



d. North of Asiatic Continent. Sea of Ochhotsk (Srandt). 



Description of the Illustrations of this Species on Plate II. 



Fig. 18. Abactinal aspect of the animal : natural size. 



19. Actinal aspect of the same specimen: natural size. 



20. Portion near the middle of a ray, actinal aspect : magnified. 



21. Portion near the middle of a ray, abactinal aspect : magnified. 



PEDICELLASTEB PAL^OCETSTALLUS, Sladen. Plate II, Figs. 22-26. 



1877. Asteracanthionpalceocrystdttus, Sladen, Ann. & Mag. Nat. Hist. ser. 4, vol. xx. p. 455. 

 1880. Pedicellaster paleeocrystullus, Sladen, Ann. & Mag. Nat. Hist. ser. 5, vol. v. p. 216. 



In general appearance this Starfish bears strong resemblance to a small Cribrella, the 

 rays, five in number, being round and tumid ; they are long, somewhat swollen out on 



