66 PXHINODERMS OF THE BRITISH ISLES 



pair of smaller lateral ones. R = ca. 4-5 r. Grows to a size of at 

 least lOo em. R. Colour in life rosy. 



Biology and development unknown. 



In British seas this species has been found at 51° 15' N., 

 12° 17' W., ca. 1200-1600 m. (" Helga "), and 57° 41' N., 11° 48' 

 W., 1853 m. (" Michael Sars "). Otherwise it is distributed as 

 far south as the Cape Verde Islands and the Azores. Known 

 bathymetrical distribution, 1095-2165 m. 



6. Lepty chaster E. A. Smith. 

 {Syn. Leptopty chaster E. A. Smith.^) 



Disk fairly large ; arms rather broad, low, with rounded sides. 

 ^Marginal plates covered with grains alone, without an}'^ larger 

 spines. Upper marginal plates much smaller than the lower ones. 

 Oral interradial area rather large. No pedicellariae. 



Only one species known from European seas. 



1. Lejity chaster arcticus (M. Sars). (Fig. 38.) 



(S}Ti. Astropecten arcticus M. Sars.) 



Adambulacral plates wdth 3-4 fairly long and slender furrow 

 spines ; outside these some other spines of decreasing size, not 



Fig. 38. — Leptyckaster arcticus, oral and aboral side. Nat. size. 



regularly arranged in series. Paxillae of the dorsal side not 

 distinctly arranged in transverse series. R==ca. 2-3 r. Colour 

 in life orange or light reddish. 



^ This latter form of the name is etymologieally the more correct and 

 should, perhaps, be preferred. 



