180 THE VOYAGE OF H.M.S. CHALLENGER. 



Table of Species of Ophiacantha — continued. 



About eleven mouth papillae to each angle ; large ) _ , . ,, ... 



. , * r ° ' e > Ophiacantha cicspidata. 



tentacle scales, . . . -J 



'Oi 



00 



s 



I 



2 



.a 

 o 



^> 

 o 



o 



CO 



Mouth papillae long and > 

 slender. 



Seven mouth papilla to each angle ; slender spini- ) 01dacaniha lmv ,;, h ^ 

 form tentacle scales, . . . . J " 



Seven mouth papillae. High disk stumps with 1 



thorny sides and ends. Arm spines feebly > Ophiacantha nodosa. 

 thorny. Six arms, . . . .J 



The lowest arm spine thickened and curved, ..... Ophiacantha cornuta. 



Tentacle scales with long thorns ; arm spines strongly thorny, . . Ophiacantha aspera. 



Nine rather short, scarcely thorny arm spines. Side arm plates barely meeting j 



above and not prominent, so that the upper arm spines on either side \ Ophiacantha indica. 

 are widely separated. Disk crotchets close-set and rather coarse, . J 



Seven strongly thorny arm spines. Side arm plates very prominent. Coarse ) Vphiacant]ia gteUata. 

 disk crotchets, . . . . . . . • j 



Arm spines strongly thorny; tentacle scales long, stout, and sharp, . . Ophiacantha seutata. 



Eight or more feebly thorny arm spines ; side arm plates not very prominent. ) Q p j liaeantlla cosm ; ca 

 Disk crotchets rather stout, . . . . . • ) 



Ten slightly thorny arm spines, longer than in Ophiacantha cosmica, . Ophiacantha millespina. 



Seven to eight slender, nearly smooth arm spines. One narrow spine-like 1 



tentacle scale. Under arm plates much wider than long of a broad axe- > Ophiacantha discoidm. 

 shape, . . . . . . . . . ) 



Seven scarcely thorny arm spines ; side arm plates very prominent. Disk ) 0p j liacant j ia pm tacrinn*. 

 crotchets minute, . . . . . . • f 



Six not thorny rather short arm spines; side arm plates not very prominent. ) Maeantha abyssico la. 

 Disk crotchets hue and close-set, . . . . . J 



Very long not thorny arm spines; side arm plates large and swollen ; outer ) ^ iaC(XM ^ l ev ispina. 

 side of under arm plates strongly curved, . . . • ) 



Disk evenly set with minute bifid or trifid stumps. Four to five sharp, slightly \q i • n , m fj n inline' 

 rough, glassy arm spines, not as long as a joint, . . . . / 



Disk beset with minute grain-like stumps bearing a crown of blunt thorns. Arm \ 



spines long, slender, translucent, and thorny, mounted on very projecting /• Ophiacantha serrata. 

 side arm plates which meet above, . . . . . . j 



Disk covered with soft skin, through which a fine scaling may be distinguished ; "\ 



and set above with a few pointed, rough, stout spines. On each angle, eleven (_ Qnhiacantha marmpiaMs. 

 scattered spine-like mouth papillae. Three slender, nearly smooth, rounded, t ^ 

 tapering arm spines, . . . . . . . . ) 



