OPHIITBOIDEA FROM THE KOREAlsr SEAS. 457 



broader thau long, angular and sharp within, curved broadly 

 without, with short straight sides ; it is convex, and separated 

 from those nest to it by the side arm -plate junction. Towards 

 the tip of the arm the lower arm-plates are very small, widely 

 separated, and about as broad as long, angular within and broadly 

 curved without. 



The side arm-plates are largely developed and form much of 

 the arm. They are long, broad, stout, and flap-like, standing 

 away from the arm at the base, especially below. They are closer 

 to the arm lower down, are convex and swollen, and have large slits 

 between them. They meet below between the seventh and eighth 

 lower arm-plates, and gradually form much of the lower surface 

 of the arm. They form the whole of the thick side of the arm 

 and a large portion of the upper surface also. Above, they are 

 close to the arm, are swollen and long, and their distal edge is 

 curved gracefully. They unite between the seventh and eighth 

 plates, and form much of the end of the arm. There are eight 

 spines on the third side arm-plates ; and they are not quite on 

 the middle of the free edge, but on its outside, the tentacle-scales 

 being nearer the other edge. The spines are very short, often 

 flat, rounded and sharp, unequal, and some are broader than 

 others. Towards the end of the arm there are five subequal 

 spines, all very short. 



Tubercle-scales. — The tentacular opening, at the side of the first 

 lower arm-plate, is long, and there are four moderate-sized scales 

 on either side of it ; the second, not so long, has three more or less 

 perfect, flat, short, rounded tipped scales on the side arm-plate, 

 and two on the side of the lower arm-plate. About the sixth Or 

 seventh plate there is a tentacle-scale on the side arm-plate and 

 on the lower arm-plate ; and then they frequently, but not inva- 

 riably, cease to be noticed, the small one on the side arm-plate 

 often remaining. 



A smaller specimen than the type, and having the disk about 

 one half the size, shows some variation in structure which should 

 be noticed. 



The principal disk-scales are represented, but are slightly com- 

 pressed ; they have the patterns of dots and furrows on them. 

 The first and second upper arm-plates have spines on them ; and 

 the side arm-plates unite, either between the fourth and fifth or the 

 fifth and sixtb upper arm-plates. Beneath, the tentacle-scales are 

 carried on nearly to the end of the arm on the side arm-plate, 



