REPORT ON THE OPHIUROIDEA. 



179 



Disk closely beset with 

 short smooth stout 

 spines, sometimes 

 mingled with grains. 1 Eight arm spines; outer ends of radial shields naked, 



Arm spines not 

 thorny. 



Disk beset with small 

 short stumps or 

 grains, more or less 

 thorny. Arm spines 

 stout, opaque, and 

 scarcely thorny. 



Table of Species of Ophiacantha. 



f Four arm spines. Disk minutely tuberculous, . . Ophiacantha tuberculosa. 



J >isk closelj' beset with 



grains or minute Seven slender translucent arm spines. Some smooth ) „ , . ,, 



tubercks. Ana] spines on disk, . . . . . } Ophiacantha cprahca. 



spines smooth. 



[ Ten arm spines. Outer ends of radial shields naked, . Ophiacantha granulosa. 



Spines and grains on disk ; outer ends of radial shields ) „ , . , , 

 naked ; numerous (16) mouth papilke, . } Ophiacantfui st rtata. 



Oph iaca nth a spectdbUis. 



[ Eleven arm spines. Radial shields covered, . . Ophiacantha rosea. 



Seven mouth papilla? in adult, and eleven or twelve arm ) „ , . ,, 



a- ________ } Ophiwont hi Vietnam. 



spines. Six or seven arms, . . . ■ j 



Large tentacle scale. Five arms ; seven or eight arm spines, Ophiacantha bidentata. 



Large tentacle scale. Five arms ; six arm spines ; a lozenge ) „ , . ,, . 



like raised figure at inner end of under arm plate, . / Ophiacantha placentigera. 



Large tentacle scale ; six arms ; seven arm spines, . Ophiacantha anornala. 



Slender tentacle scale ; six arm spines, . . . Ophiacantha imago. 



-rv , , , , f Seven long, slender, much flattened arm spines. Outer ) „ 7 . ,, 



D.sk evenly granulate. <j mouth p * apilla spatlda shaped; . . .} Ophiacantha valmcimnsi. 



Disk spines with forked heads, and covered with thick | 



skin. Arm spines scarcely or not at all thorny. One V Ophiacauflta sentosa. 



Disk beset with short 

 slender spines. 



minute short tentacle scale, 



■ 



Disk spines simple. Arm spines not thorny. One or 

 two large, long tentacle scales, 



J- Ophiacaittlta stimulea. 



Disk spines with forked heads. Arm spines slender and ) r . , . _,, , . 

 ,, , x > Ophiacantha ecmnulata. 



Spines of disk and arms slender and translucent. Arm ) n ; . , . 

 spines not thorny. Some thorny stumps on disk, ./ ™ 



> Ophiacantha hirsuta. 



> Ophiacantha abnormis. 



Mouth angles elon- 

 gated, and bearing 

 twelve to fourteen 

 papillae. 



Arm spines flattened and serrated 

 on edges, 



Arm spines smooth , rounded, slender, 

 tapering, 



Disk beset with small 

 spines or grains. 

 Radial shields mak- 



Disk beset with stout spines, essentially smooth, and ) 



with gTains. Arms about twelve times diameter of > Ophiacantha troschdi. 



disk. Radial shields partly naked, . . .J 



ins narrow radiat- J. Disk beset with thorny grains and spines. Radial shields ) „ ,. 



in| ridges; arms covered, . . . . . j Ophiacantha 



long (8-12 times 



diameter of disk). Disk beset with thorny grains and spines over its whole ),-.,. J7 



[ surface. Radial shields covered, . . . j Ophiacantha ,„„//,. 



