112 ECHINODERMS OF THE BRITISH ISLES 



Greenland to 8]^itzbergen and the Kara Sea, in 30-350 m. depth : 

 on the Norwegian coast it has been found as far south as the 

 Trondhjeni Fjord. It may well be expected to occur also in the 

 cold area of the Faroe Channel. Solaster ahyssicola has been 

 found on 45° 26' N., 25° 45' W., 3120 m. ('^ Michael Sars "), and 

 may thus be expected to occur also in the deep water off Ireland. 

 It is elsewhere known from off the N. American coast, in depths 

 of ca. 1540-3800 m. These two species are therefore included in 

 the key. 



Key to the species of Solaster hnown from or likely to occur 

 in the British seas. 



1. A single series of larger marginal paxilhe .... 2 

 A double ,, ,, ,, ,,.... 4 



2. The dorsal skeleton consists of narrow bars forming an open, 



irregular network (Fig. 66, 1) . I. S. papposus (Linn.) 



The dorsal skeleton scale -like or stellate .... 3 



3. The dorsal skeleton scale-like, imbricating plates forming a very 



close covering (Fig. 66, 2), leaving only very small open spaces, 



containing single papulae . . 2. S. squamatiis Doderlein 



The dorsal skeleton stellate plates forming a quadrate mesh work 



(Fig. 66, 3) ; 3-7 papulae in each interspace S. ahyssicola Verr. 



4. Paxillse of dorsal side very close, flattened ; mostly 4 large, 



conspicuous furrow spines . . S. glacialis Dan. and Kor. 



Paxillae of dorsal side, more or less scattered, not flattened ; mostly 



2-3 small, inconspicuous furrow spines 3. S. endeca (Linn.) 



1 . Solaster ( Crossaster) papposus (Linnaeus) . (Fig. 67 ; Fig. 66, 1 . ) 



(Syn. Solaster affinis Koren and Danielssen.) 



Rays 8-13, mostly 10-12. Dorsal skeleton (Fig. 66, 1) con- 

 sisting of narrow bars forming an irregular reticulation, enclosing 

 fairly large membraneous spaces in which several papulae are 

 found. Paxillae large, broom-shaped, with rather long, slender 

 spines ; they are fairly distant, the covering of the dorsal side 

 thus rather sparse. Marginal paxillae large and conspicuous, in a 

 single series. Furrow spines varying in number, mostly 3-5, long 

 and slender. A transverse series of 5-9 somewhat longer spines 

 on the adambulacral plates. R = ca. 2 r. Grows to a very con- 

 siderable size, up to ca. 340 mm. diameter. Colour in life rather 

 variable, but mostly the disk is purplish-red, the arms whitish, 

 with a broad red transverse band ; more rarely it is uniformly 

 purple on the dorsal side. Oral side whitish. It is, indeed, a 

 splendid form, justly called " sun- star ".^ 



' " The Solasters are suns in the system of Sea-stars " (Forbes, British 

 Starfishes, p. 110). 



