Mr. J. A. Stewart on Asteronyx Loveni. 77 



But a closer mvestigation leads me at once to acknowledge my error ; 

 for, looking especially to the comparative anatomy, and believing, as 

 I do, that time and circumstances may produce essential alterations 

 in the habits and in the external form, colour, and size of animals, 

 I think that there are more unstable and far-fetched theories in phy- 

 siology than the belief that the hare and the rabbit may have been 

 originally one and the same animal. 



March 12, 1861.— John Gould, Esq., F.R.S., in the Chair. 



Descriptiox oy Asteronyx Loveni, Mull, et Trosch., 

 A NEW British Starfish. By John A. Stewart, New 

 College, Edinburgh, 



This fine Starfish belongs to the Euryalece. It is the second spe- 

 cies of this division of the OphiuridcB which has been noticed in the 

 British seas ; and it is the more interesting as it is a form interme- 

 diate between the already known species {Astrophyton scutatuin, 

 Link) and the simple-rayed Ophiuroe, having the prehensile scaleless 

 arms, and the radiating body-ribs of the other EuryalecB, joined with 

 the undivided arms of the Ophiurce. As in Astrophyton, it wants 

 the mouth-plates between the origin of the rays, but has instead a 

 strong calcareous bar uniting the bases of the two neighbouring arms. 

 The two genera have also the raadreporiform tubercle on the under 

 surface in one of the interbrachial angles nearest the mouth. The 

 genus Trichaster is generally placed between Astrophyton and Aster- 

 onyx, but it has the interbrachial mouth-plates, and wants the ma- 

 dreporiform tubercle ; indeed it seems scarcely separable from Ophio- 

 scolex, except in possessing prehensile divided arms, and would per- 

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

 true Ophiurce. 



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 fur Naturvidenskaberne, vol. ix. p. 96). 



The specimen from which MuUer and TroscheUs description was 

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

 near Hammerfest, Norway. 



Description of Asteronyx LoTcni, Mull. ^ Trosch. 



The body is pentangular. The skin, which covers the body an3 

 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 sUght 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. 



