OPHITIEOIDEA TROM THE KOREAN SEAS. 



471 



two, three, or more before the next band. In some parts many- 

 plates are covered longitudinally -u-ith a stripe of the green tint. 

 The edges of the radial shields and some of the scales of the disk 

 are tinted with the dark colour, but the traces of it below are 

 slight. 



Locality. Korean seas. Collected by Capt. St. John, R.IN'. 

 In the British Museum. 



Genus Ophiacantha, Mull. ^ Troschel. 



Ophtacaxtha Dallasti, sp. nov. Plate XI. figs. 25, 26, 27. 



The disk is small, pentagonal, and contracted in the inter- 

 brachial spaces. The radial shields are entirely hidden ; but 

 their outlines, long and narrow, can be traced beneath the cover- 

 ing, which, like that of the rest of the disk, is ornamented with 

 microscopic stumps, each terminating in three wide-apart sharp 

 thorns, there rarely being two and four terminal ones ; stumps 

 slightly larger in the centre of the disk. 



The under surface of the disk is covered to the outer edge of 

 the mouth-shields with the same texture, the thorned stumps being 

 small and crowded. Each stump is on a rounded base, the aggre- 

 gate of which form the membrane of the disk. 



The mouth-shields are very small, heart-shaped, augular within, 

 rounded without, and longer than broad; they are marked with a 

 central splash of purple colour. 



The side mouth-shields, much larger than the mouth-shields, are 

 nearly united within, and extend on either side outwards beyond 

 the broadest part of the mouth-shield, and come in broad contact 

 with the first side arm-j)late. These side shields are broad from 

 side to side, and their inner edges long, are shorter than the outer, 

 where the shield is largest ; their outer edge partly bounds tho 

 generative opening. The jaws are short and broad from side to 

 side, so that the angle is not a very acute one. The mouth- 

 papillse are seven on each angle ; the inner one, below the teeth, is 

 markedly larger and longer than the others, and it is somewhat 

 in the shape of a long sharp fir-coue. The next and neighbouring 

 papillae are more spiniform, and the most external on either 

 side are broader and shorter than the others. The teeth are four 

 to each jaw, and they are longer than broad, and flat, rounded 

 within. 



The arms are about six times as long as the diameter of tlie 

 disk, and are very nodose in appearance from the swollen nature 



