VIOLET CTIOSSFISH. 93 



and affords the best characters for the distinguishing of 

 species in this genus. The colour of Uraster violacea varies 

 much, and is often very beautiful, being of a bright orange, 

 or rich red, with blue spots, and beneath not uncommonly 

 straw colour. Frequently the rays are of a livid purple 

 towards their extremities. The bases of the spines are 

 often surrounded with a ring of blue. The madreporiform 

 tubercle is very lateral, the strise coarse, undulating and 

 radiating from the centre, often bifurcating towards the 

 base. 



This species is apparently gregarious, and somewhat 

 confined in its habitats. In the Frith of Forth it is ex- 

 ceedingly abundant. Off Anstruther, at the mouth of the 

 Frith, it is by far the commonest species ; and the fisher- 

 men bring up great numbers of them on their lines, while 

 Uraster rubens seldom occurs. Dr. Johnston informs me 

 that it is the most common species on the coast of Ber- 

 wickshire, while the rubens is rare. High up the estuary 

 of the Forth the rubens is common, and violacea scarce. 

 In some parts of the Irish Sea it is not to be met with. 

 On the coast of Ireland, however, Mr. Thompson states 

 it is common at Belfast, Dublin, and Youghal, and is 

 found mixed with rubens. Mr. Goodsir and I took it in 

 Orkney and Shetland. At Scalloway in the Shetland 

 Isles we found a remarkable variety, which at first sight 

 had much the aspect of a distinct species. The rays 

 tapered from their bases and were very narrow. The 

 central and lateral ridges of spines had the spines placed 

 at considerable distances from each other in an extremely 

 regular manner. The spinules round the bases of the 

 spines, which were as usual in this species long and taper- 

 ing, were highly developed. Very few spines were scat- 

 tered over the reticulations of the rays ; but a good num- 



