CLARK: BRITTLE-STARS. 291 



wider without, where separated by first under arm-plate, than within, 

 where they meet. Oral plates, small but distinct. Oral papillae, 3 

 on each side, quite thick, the most proximal, at the tip of the jaw, 

 block-like; distal papilla much the largest, somewhat fan-shaped. 

 First under arm-plate moderate, rectangular, much wider than long; 

 succeeding plates similar but much larger, distal margin slightly 

 concave, corners rounded, in contact for full width; distal portion of 

 basal plates distinctly swollen. Side arm-plates very small, each 

 bearing 3 subequal, blunt, little flattened arm-spines, distinctly longer 

 than the arm-segment. Tentacle-scales 2, moderately large. Tenta- 

 cle-pores very large. Color, in life and as preserved, variegated gray 

 and white above, nearly white below; the upper arm-plates show 

 much diversity and no sort of sequence in ground-color, but the distal 

 margin is generally white and often back of that is an indistinct 

 dusky transverse band. 



This species resembles Ophiophragmus ivurdcmanii so much in its 

 superficial appearance that it was supposed to be that species, when 

 taken. But there is no hint whatever of marginal papillae and the 

 differences in disk-scaling and arm-spines cannot be ignored. It is 

 also very near Amphiodia atra, A. riisei, and A. pJanispina but the 

 smaller radial shields and tentacle-scales and the smaller and sharper 

 arm -spines distinguish it from A. atra, the very much longer arms 

 separate it from A. riisei at a glance, and the finer disk-scaling and 

 slenderer arm -spines show it is not A. p)lanispina. 



Amphioplus coniortodes, sp. nov. 

 ■loptu8t]s = powdery, like dust, in reference to the very fine disk-scaling. 



Plate 7, fig. 3, 4. 



KOV 



Holotype.— M. C. Z. 4,217. Florida: Key West, June 1917, in 

 sandy mud near a mangrove key, in 1-2 ft. of water, with Amphioplus 

 ahditiis and A. thrombodcs (p. 292). Carnegie Expedition. H. L. 

 Clark coll. 



Disk distorted, but doubtless 6-7 mm. in diameter; arms 75-85 mm. 

 long. Disk covered by a coat of exceedingly fine scales; those along 

 the interradial margins are conspicuously larger, the largest being 

 next to the distal end of the radial shields. The latter are quite small, 

 about three times as long as wide, with the pointed proximal ends 

 separated by a few scales and the wide distal ends in contact. Upper 



