OPHIUROIDEA 179 



two inwardly-directed processes at the point. Colour of larva a 

 faint yellowish. 



This species is remarkable for its power of climbing ; 

 especially it climbs Laminarians, the huge leaves of which it 

 may in places (at any rate at the Norwegian coast) literally cover 

 up to the surface of the water. It often climbs the sides of 

 aquaria, attaching itself there with a pair of its arms, its other 

 arms stretched out under the surface of the water. The tube- 

 feet are very strongly papillate ; the sUme secreted by these 

 papillae serves for attachment. The food appears to consist 

 partly of plants (parts of the Laminarias), but it feeds also on 

 all sorts of small animals. It is known to eat dead fishes, and 

 it is sometimes found in great numbers on fishes caught in the 

 nets. It is eaten by sea-stars and decapod Crustaceans, but 

 apparently not by fishes. It prefers a stony bottom. It has 

 been observed in places with a rather strong current to sit on 

 the bottom with some of the arms stretched upwards, free in the 

 water, apparently for the purpose of collecting food, which is 

 probably caught in the slimy secretion of the tube-feet. 



In British seas this species is common all round the south and 

 west coasts ; on the east coast it goes at least as far south as 

 the Durham coast, while it does not appear to occur in the open 

 North Sea. It is elsewhere distributed from the Trondhjem Fjord 

 on the Norwegian coast down to the Azores and the Mediter- 

 ranean. The bathymetrical distribution is 0-ca. 400 m., but it 

 appears to be rather rare below ca. 100 m. 



2. Ophiopsila Forbes. 

 (Syn. Ophianoplus M. Sars.) 



Scales of disk not covered by granules ; the scales are exceed- 

 ingly fine, giving the impression of the disk being naked. Radial 

 shields small, partly or wholly concealed by the scaling. Arm 

 spines short, outstanding, flattened, but not otherwise specialised. 

 The inner tentacle scale very long, flattened, dagger- shaped, cross- 

 ing that of the opposite side in the mid-line on ventral surface 

 of arm (Figs. 101, a; 102, a). Teeth with an enamel cap. 



The elongate tentacle scales are covered with a thick, gland- 

 ular, strongly ciliated skin ; a band of this ciliated skin across 

 the ventral side of the arm connects the two ciliated spines of 

 each segment. These ciliated parts produce a current along the 

 ventral side of the arm, which may perhaps have the function 

 of leading food particles to the mouth. The ciliated spines, the 

 lateral plates and, partly, the arm spines, are strongly luminescent, 



