114 ART. 2. — H. MATSUMOTO: 



ed with a few thorns. Eadial shields raised, long, narrow, about 

 two-thirds as long as the disk radins, those of the same pair 

 parallel to each other. They are covered by the skin, and usually 

 also by the scales except at the outer ends. In some specimens, 

 they are almost entirely fi^ee from the scales. Interbrachial ventral 

 surfaces similar to the dorsal side, but the stumpy tubercles are 

 fewer and finer. Genital slits large, long, almost reaching the 

 disk margin, much widened and rounded at the inner ends. 



Oral shields small, rhomboidal, with concave sides and 

 perfectly rounded lateral and outer angles, inner angle like a 

 beak, so that the inner sides form a brace-shape ; very short, 

 about twice as wide as long. Adorai shields large, stout, with 

 concave adradial side, more or less separated fi'om each other by 

 a naked, depressed space, or sometimes entirely in contact. Three 

 or four oral papillœ on either side, long, conical, rather obtuse ; 

 the outermost one is directed laterally and protects the second 

 oral tentacle pore ; the next is the stoutest. Five or six teeth, 

 obtuse or sometimes widened at the free end, with two or three 

 irregular denticles, except the uppermost one, which is acute and 

 is the longest. 



Arms rather stout, uniformly tapered, knotted, with very long 

 joints. First two dorsal arm plates quadrangular, with very 

 convex outer side, wider than long, in contact with each other. 

 The second is the largest, and is wider without than witliin. 

 Those following are small, triangular, with very convex outer side, 

 slightly longer than wide, not in contact with each other. Lateral 

 arm plates well developed, with prominent spine ridges, meeting 

 each other aljove and below, except between the first and second 

 ventral arm plates and between the first and second dorsal plates ; 

 besides, the second and third dorsal plates often do not meet, 



