160 ECHINODERMS OF THE BRITISH LSLE8 



In British seas this species appears to be rather rare, having 

 been found only off Aberdeen, Moray Firth, the Minch, Loch 

 Torridon, Loch Hourn, and Firth of Lorn ; more recently it has 

 been recorded from off S.W. Ireland (" Mich. Sars "). Otherwise 

 it has an almost cosmopolitan distribution, being known from 

 the Scandinavian seas to Finmark in the north, from the 

 American coast down to the West Indies ; farther from Cape, 

 the Indian Ocean, and the Pacific from Australia to the Bering 

 Sea. The bathymetrical distribution is ca. 100-ca. 1800 m.^ 



II. Family Gorgonocephalid^ 



Disk large, covered with grains, spines, or a naked skin. 

 Arms simple or branching, covered with grains and, at least on 

 the finer branches, bearing rings of fine, microscopical hooks. 

 Mouth papillae spiniform. Arm spines (or tentacle scales) small. 

 One or five madreporites. A bundle of short caeca proceed from 

 the water vascular ring in each radius.^ 



Only one genus represented in British seas. Another genus, 

 Astrospartus Doderlein, with the species A. mediterraneus (Risso), 

 occurs in the Mediterranean and along the Moroccan coast, at 

 least down to Cape Blanc. It is not known farther north, and 

 as it is a littoral form, there is scarcely any prospect of finding it 

 in the British seas. (It is easily distinguished by the tentacle scales 

 lacking on the inner part of the arm, unto the first division.) 



1. Gorgonocephalus Leach. 



Arms branched from the base ; arm spines (or tentacle scales) 

 beginning at the second pair of tube-feet. Only one madreporite. 

 A series of plates along edge of disk in the interradial spaces. 

 Genital organs small, very numerous, in several series on the 

 bursae, which latter are all in mutual connection. 



The species of this genus live rather gregariously ; on rocky 

 ground, swept by currents, they may be found in great numbers, 

 covering the ground, clinging to one another, their richly branch- 

 ing arms forming a dense network in which are caught the 

 pelagic organisms (Copepods, Appendicularians,etc.) on which they 



^ The statement that it was found in a depth of only 9 fathoms in Loch 

 Torridon (Stewart) is probably due to some mistake ; it has otherwise never 

 been recorded from so small a depth. 



2 Possibly corresponding to the " Tiedemann's bodies" in Asteroids, 

 which are also organs attached to the watervascular ring. Till now known 

 only in this genus, but will probably be found to be a family character. 



