114 KCHINODERMS OF THE BRITISH ISLES 



small paxilla3). Jaws with 9-10 spines in the superficial series 

 (generally only 2-5 in the typical form). Rays 10. It appears 

 that the variety anglica Doderlein is the same as septentrionalis, 

 the only appreciable difference being that it has 12 arms, which 

 is hardly a constant character. 



The development is direct, without a Bipinnaria stage. The 

 food consists mainly of other Echinoderms, especially sea-stars 

 (Asterias) and sea-cucumbers {Psoitis) ; Molluscs may, however, 

 also form the chief part of its food, and it is reported to feed on 

 oysters, thus doing harm on oyster banks. It is also recorded as 

 eating Actinians ; it is very voracious, and is able to devour sea- 

 stars almost as large as itself. 



In British seas this species appears to be common all round 

 the coasts, from low- tide mark down to ca. 50 metres or more. 

 It is elsewhere distributed all over the Arctic region, its southern 

 limit in European seas being the Channel. On the American 

 Atlantic coast it goes down to 40° N. ; in the Pacific it goes down 

 to Vancouver on the American, to the Ochotsch Sea on the 

 Asiatic side. Bathy metrical distribution : 0-ca. 1200 m. The 

 variety septentrionalis is recorded only from the Faroe Channel. 



2. Solaster squamatus Doderlein. 



Rays 9-11. Dorsal skeleton (Fig. 66, 2) consisting of imbri- 

 cating plates forming a close, almost scale-like covering, leaving 

 only very small spaces between them in which generally only a 

 single papula is found. Paxillae mainly like those of the pre- 

 ceding species, but rather smaller and of more uniform size. 

 Marginal paxillae in a single series. Furrow spines 5-7. A trans- 

 verse series of mostly 8 spines on outer surface of adambulacral 

 plates. R = ca. 2-2-25 r. Appears to reach not nearly so large a 

 size as S. papposus, the largest size recorded being 107 mm. 

 diameter. Colour in life orange-red, with yellowish-red paxillae ; 

 3'ellowish- white on the oral side. 



Biology and development unknown. 



In British seas it has been found only in the cold area of the 

 Faroe Channel, 1098 m. (" Michael Sars "). It is mainly, 

 though not quite exclusively, a cold-water form, occurring as far 

 north as Spitzbergen and East Greenland. Bathymetrical dis- 

 tribution : ca. 100-1160 m. 



