1861.] MR. J. A. STEWART ON ASTERONYX LOVENI. 97 



haps.be more correctly placed by the side of this genus among the 

 true Ophiuree. 



The specimen now exhibited was found in Loch Torridon in Ross- 

 shire, in the summer of 1859. I took it from the deep-sea lines 

 which had been set in a part of the loch 9 fathoms deep, and having 

 a rocky bottom. Koren records this species as occurring on the 

 coasts of Norway at a depth of from 50 to 150 fathoms (Nyt Maga- 

 zin fiir Naturvidenskaberne, vol. ix. p. 96). 



The specimen from which Miiller and Troschel's description was 

 taken is in the Museum at Stockholm. It was found at Bohuslan, 

 near Hammerfest, Norway. 



Description of Asteronyx loveni, Mull. ^ Trosch. 



The body is pentangular. The skin, which covers the body and 

 arms, is naked, without scales or granules. On the upper surface 

 of the body, covered by the skin, are ten radiating ribs in subparallel 

 pairs ; they rise from the margin of the body, on either side of the 

 arms, and, passing inwards, unite, leaving a small central portion of 

 the disk free ; they are cartilaginous and flat, with a slight depressed 

 central groove : very much reduced in size, they are continued on 

 the under surface of the body, along the margin of the arms, to the 

 genital openings. 



The mouth is five-radiate, and placed in the centre of the under- 

 surface of the disc, in the midst of the origin of the arms ; a strong 

 osseous bar, taking the place of the interbrachial plate of the Opkiura, 

 unites the bases of the arms, and forms a solid ring round the mouth ; 

 the five bars give origin to as many calcareous cones, which passing 

 inwards nearly meet in the centre ; the intervening spaces form the 

 five-radiate mouth. Articulated to the cones are a number of spines, 

 which increase in number and length towards the apex ; behind the 

 base of the cone, in the angle of each interbrachial space, is placed 

 two genital openings ; the madreporiform tubercle also occupies the 

 angle of one of these spaces. 



The arms are convex above, and quite flat on the under surface ; 

 they are composed of narrow calcareous joints, each of which is 

 furnished with appendages on the inferior angles ; on the second 

 joint from the base of the arm a single short spine appears on either 

 side ; before the arm leaves the disk, the number increases to three 

 or four, the one on the inner side being longer than the others ; 

 these spines are articulated to calcareous processes, with socket de- 

 pressions for the insertion of the ball-joint of the spines ; the pro- 

 cesses are scarcely visible at first, but increase in size, until, beyond 

 the middle of the arm, their margin supplies space for the attach- 

 ment of no fewer than twelve very short spines. The inner spine gra- 

 dually increases in length from the base of the arm until it reaches 

 its maximum about 2 inches from the disk ; soon thereafter it begins 

 to decrease, and continues until it becomes of the same size as the 

 others. This long slender spine is directed inwards on the flat under- 

 side of the arm, and reaches at its greatest length fully two-thirds 



Proc. Zool. Soc— 1861, No. VII. 



