202 ECHINODERMS OF THE BRITISH ISLES 



to 1765 m. It is elsewhere known along the Scandinavian coasts 

 from the Skagerrack to the Trondhjem Fjord, and towards the 

 south to S. of the Canaries. It is not known from Greenland 

 or the American coasts. 



2. Ophiactis abyssicola (M. SsiTs). (Fig. 114.) 



(Syn. Amphiura abyssicola M. Sars ; Ophiactis poa Lyman ; 

 0. corallicola Koehler.) 



Disk with rather coarse scales, those on the oral side much 

 finer ; the primary plates are fairl}^ distinct. Rather coarse spines 

 scattered both on dorsal and oral side ; radial shields fairly large, 

 not very broad, separated by a single row of scales. Arms 5. 

 Dorsal j^lates of arms broad, fan-shaped, contiguous ; ventral 

 plates with produced outer corners. One tentacle scale (excep- 

 tionally 2). Arm spines 4, farther out 3, rather slender. Mouth 



Fig. 114, — Ophiactis abyssicola. 1. Dorsal side. 2. Oral side. x 4. 

 (From Damnark's Fauna.) 



shields rhombic. Two broad, scale-Hke mouth papillae on each 

 side of jaw. Colour in life reddish, in alcohol usually bluish-grey. 

 Grows to a size of 8-9 mm. diameter of disk. Arms ca. 6 times 

 as long as the diameter of disk. 



It occurs among corals and alcyonarians, and especially on 

 the Bird's-nest sponge, Pheronema. Development unknown. 



In British seas this species is one of the commonest Ophiuroids 

 in deep water off the Irish coasts. Also found on the Lousy Bank 

 and in the Faroe Channel (" Porcupine "). It is elsewhere 

 distributed from Finmark to the Bay of Biscay and the Azores, 

 and even to S. Africa. Also known from Greenland. Bathy- 

 metrical distribution ca. 125-1850 m. 



Ophiactis corallicola Koehler can scarcely be maintained as a 

 separate species. The characters by which it is to be distinguished 

 from abyssicola are : the presence of spines only on the dorsal side 

 of disk, and the emarginate edge of the disk in the interradii ; 



