106 Rev. A. M. Norman on the Genera and 



lary spines on the margin, increasing in length and size towards 

 the mouth, being most developed on the maxillary face. Ova- 

 rian apertures ten. A madreporiform tubercle in one of the 

 interradial spaces on the oral surface. 



Aster onyx Loveni, Miiller & Troschel. 



1842. Asteronyx Loveni, Miiller & Troschel, Syst. der Asteriden, p. 296. 

 1861. Asteronyx Loveni, Stewart, Ann. Nat. Hist. vol. viii. p. 77 and fig. 



1861 . Asteronyx Loveni, Sars, Oversigt af Norges Echinodermer, p. 5, pi. 1 . 



figs. 1-5. 



1862. Asteronyx Loveni, Dujardin & Hupe, Hist. Nat. des Zoophytes Echi- 



nodermes, p. 296. 



Disk pentagonal, covered, as are also the arms, by a naked skin, 

 wholly devoid of scales or granules ; a pair of flat cartilaginous 

 radiating ribs on the dorsal surface over the base of each arm. 

 Arms very long (greater to lesser radius as about 18 to 1), 

 convex above, flat beneath. Spines very short, originating from 

 calcareous elevated processes ; the number of spines in each 

 transverse row (contrary to what is the rule among the 

 Ophiuridse) is less at the base of the arms than at some little 

 distance from the margin of the disk ; the greatest number of 

 spines in any transverse row is twelve ; one spine in each row 

 is much longer than the rest, and more than equal in length to 

 half the breadth of the arm ; this spine is inclined inwards 

 and covered with a smooth skin, but towards the apex it is 

 furnished with several hook-formed processes. There are no 

 papillary spines over the tentacular pores. The oral aperture 

 is bounded by five strong calcareous bars, one of which forms 

 the inner margin of each interradial space. 



A single specimen is all that has as yet been found to prove 

 the existence of this fine Norwegian Echinoderm in the British 

 seas. That specimen, which is a fine example, measuring in its 

 lesser diameter If inch, and in its greater diameter 2 feet, is 

 now preserved in the British Museum. It was procured from 

 Loch Torridon, in Rosshire, in the summer of 1859, by Mr. John 

 A. Stewart, who took it from the deep-sea lines, which had been 

 set in a part of the loch 9 fathoms deep, where the bottom was 

 rocky. The occurrence of the species in the Laminarian Zone is 

 somewhat remarkable, since on the Norwegian coast, like the 

 Ast7-ophytonidce in general, it inhabits the deep sea in from 50 to 

 150 fathoms. 



Fam. II. Ophiuridse. 



Arms always simple, and (in British genera) always encased 

 by four series of scales, one dorsal, one ventral, and two lateral. 

 No radiating ribs on the dorsal surface of the disk over the origin 

 of the arms ; generally two radiating scales take their place, but 



