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ECHINODERMS OF THE BRITISH ISLES 



1. Palmipes membranaceus Linck. (Fig. 57.) 



(Syn. Palmipes placenta (Pennant) ; Anseropoda memhranacea 



(Linck).) 



Outline of body varying from perfectly pentagonal to sub- 

 pentagonal with sides markedly concave.^ The spine-groups 

 arranged in fairly regular radiating series, those of the oral side 

 slightly the larger. The adambulacral plates carry 5-6 slender 



Fig. 57. — Palmipes memhranaceus, oral and dorsal side. Somewhat reduced. 



furrow spines, united in their basal part by a web ; on the outer 

 surface there is a series of 4 small spines, likewise united at the 

 base by a fine membrane. R = ca. 1-5 r. Reaches a size of ca. 

 20 cm. diameter. Colour in life red on the dorsal side, yellowish, 

 generally with a very conspicuous band of red along the margin, 

 on the ventral side. 



It prefers sandy bottom, and appears to lie more or less 

 buried in the sand. Its food consists mainly of crustaceans 

 (amphipods, cumaceans, mysids, crabs, hermit-crabs), but it 



^ It appears that the sea-star is, to some degree, able to change the 

 outline of its body. 



