162 



ECHINODERMS OF THE BRITISH ISLES 



1. Gorgonocephalus cap2it-mecluscB (lAnnacuH). (Fig. 91.) 



(Syn. Gorgonocej^hahis Linckii (Miill. and Troschel) ; 

 Astrophyton scutaium Forbes.) 



Disk set with rather numerous short, coarse, conical spines ; 

 on the oral side in the interradial areas they are smaller, more 



Fig. 91. — Gorgonocephalus caput-medusce. Young specimen. 

 Nat. size. (From Danmark's Fauna.) 



like grains. Radial shields fairly prominent. Arms closely 

 covered by fine grains. The belts of 

 hooks distinct only after the third-fourth 

 ramification ; the hooks are ca. J mm. 

 long, glassy, with a small thorn below 

 the point (Fig. 92). They are arranged 

 in two series across the dorsal side of 

 each arm- joint, bent backwards so as to 

 turn their backs towards each other. 

 Ventral side of arms covered with small 

 grains to the mouth edge, concealing the 

 ventral ])lates. Arm spines (or tentacle 



scales) short, smooth, curved. At the iimer 2-3 pores there are 



Fig. 92. — Hook from arm 

 of Gorgonocephalus 

 caput-nieduscB. x 100. 

 (From Danmark' s 

 Fauna.) 



