286 bulletin: museum of comparative zoology. 



support for numerous, unequal blunt tubercles or papillae, 1-3 times 

 as high as thick, arranged without any apparent order. Radial 

 shields visible as areas free from these tubercles but their outlines are 

 concealed by the thick skin; they seem to be about twice as long as 

 wide and in contact except proximally. Upper arm-plates rounded 

 triangular, considerably swollen, widest near distal margin, very 

 slightl}^ in contact or (more exactly) overlapping. Interbrachial 

 areas below similar to disk but the tubercles are very much smaller. 

 Oral shields rather small, about as wide as long, with a very acute 

 angle and strongly concave sides proximally and a rounded distal 

 angle. Adoral plates relatively very large, not twice as long as wide, 

 nearly as wide within where the\' meet broadly as without where they 

 are separated by the first under arm-plate. Oral plates small but 

 distinct, not much longer than mde. Oral papillae, 3 on a side; 

 distal papilla, three times as wide as long, much wider than the other 

 two papillae together; second papilla flat, about as wide as long; 

 proximal papilla thick and block-like, but not placed at apex of jaw. 

 On one jaw, the distal papilla appears to be fused with the middle 

 papilla; at any rate it is that much wider than usual, and there is no 

 middle papilla. In another case, the distal papilla appears to have 

 divided as it is only a little more than half as wide as usual and there 

 are tivo middle papillae. First under arm-plate very small, perfectly 

 pentagonal; succeeding plates large, squarish or rounded hexagonal, 

 as wide as long, broadly in contact, but soon becoming separated and 

 then longer than wide; distal margin convex but lateral margins tend 

 to become more or less concave. Side arm-plates rather projecting, 

 meeting above and below except at base of arm ; each carries 3 small, 

 subequal, blunt arm-spines about equal to a segment. Tentacle- 

 scales 2, one on the side arm-plate and one on the under arm -plate; 

 but located far out on those plates instead of at their junction; hence 

 they seem to be distal to the tentacle, a most anomalous condition, 

 but apparently not widely different from that shown by the other 

 members of the genus. Color, dried specimen, disk, variegated with 

 blackish, gray, and whitish; arms, pale yellowish. 



The disk-covering of this species distinguishes it at once from the 

 other members of the genus except possibly A. formosa and from 

 that species, the oral papillae separate it at once. Orally the resem- 

 blance to A. africanum is quite close but the disk-covering is utterly 

 different. 



