42 OPIIIURJE. 



is, the disk is extremely soft, especially when the animal 

 is in egg - , as was the case in the instance mentioned ; and 

 not being so well secured to its skeleton, as in the other 

 Brittle-stars, it was almost always rubbed away or de- 

 stroyed by the rough usage it met with in the dredge on 

 its way to the surface. The arms, however, seem to pre- 

 serve their integrity much more patiently than those of 

 the neighbouring species. The two localities mentioned 

 are the only places in Britain where this Ophiura has as 

 yet been observed ; it is probable, however, that it will be 

 found in similar situations in other loughs on the west 

 coast of Scotland. In July 1840 it was taken for the 

 first time in Ireland by Mr. Thompson, Mr. Ball, Mr. 

 Hyndman, and myself, in the Killary and other marine 

 Loughs of Connemara. Muller first observed individuals 

 in Norway, "in sedimento argillaceo 1773, rarissime ; 

 postea in fundo argillaceo maritimo Norvegise occidentalis 

 frequentam reperi ;"" so that its habitat appears to be 

 always muddy. 



The disk is somewhat pentangular, slightly lobed and 

 notched opposite the rays. Its surface is covered with 

 minute, smooth, rosulated scales ; and opposite the origin 

 of each of the rays are two oblongo-lanceolate scales, which 

 converge, but do not touch, at their upper extremities. 

 The arms are extremely long, though variable in their 

 length in various specimens ; in some, ten or twelve times 

 as long as the breadth of the disk, and of nearly equal 

 thickness to near their extremities, where they suddenly 

 taper to the termination. They are covered above with 

 square scales, below with lenticular plates. Muller reckon- 

 ed no less than one hundred and thirty-four joints in each 

 arm of one of his specimens. Their sides are clothed with 

 spines, which are rough and conic, scarcely as long as half 



