98 ECHINODERMS OF THE BRITISH ISLES 



II. Family AsTERiNiDiE 



Dorsal side covered with imbricating, scale-like plates carrying 

 small spines placed in irregular groups or in paxillae-like tufts. 

 Body rather pentagonal, flattened, with a sharp edge, formed 

 by the small, mostly rather indistinct marginal plates. Oral 

 interradii large, with regular, imbricated plates carrying a few 

 spinelets or granules. 



Two genera in the British (and European) seas. 



Key to the geyiera of Asterinidce of the British seas. 



Body very flat and thin, with a crest-like thickening along each 

 ray. Very large, 10-12 cm. diameter . 2. Palmipes Linck 



Body slightly swollen, not very thin ; no crest along rays. Small, 

 4-6 cm. diameter . . . . .1. Asterina Nardo 



1. Asterina Nardo. 



Body subpentagonal ; dorsal side slightly swollen, oral side 

 flat. Rays short ; no crest along the mid-dorsal line. Spines 

 small, arranged in irregular groups on the dorsal side, fewer and 

 somewhat stronger on the oral interradii. Papulae in five broad 

 radial areas and on middle of disk. Simple pedicellarise may 

 occur. 



Only one species in British (and European) seas. 



1. Asterina gibbosa (Pennant). (Fig. 56.) 

 (Syn. Asteriscus verruculatus Miiller and Troschel.) 



Spines on the dorsal plates in groups of 4-8. Pedicellarise, 

 formed by two slightly curved, opposing spines, not rarely found 

 between the spine groups. Spines of oral interradii in groups of 

 2-3, somewhat larger than those of the dorsal side. Adambulacral 

 plates with 4 furrow spines and 2 on the outer surface. Female 

 genital openings on the oral side, large and conspicuous. R= ca. 

 1-2-2 r. Reaches a size of ca. 6 cm. diameter. Colour in life, 

 olive-greenish, or yellowish or brownish-red. 



It is mainly a littoral species, living on and below stones, but 

 may also be found among algae, Zostera, sponges, etc. In deeper 

 water it occurs mainly on shell bottom. It feeds on various 

 molluscs, but also on worms and echinoderms (Ophiurans). 



The eggs, which are -5 mm. in diameter, are deposited in small 

 groups on stones, etc., to which they remain attached. While in 

 the act of shedding the eggs the female is generally accompanied 



