II. Arbeiten von speciellerem Character etc. 3. Ophiuroidea. 193 



ranged in tufts on the mouth-frames and jaw-plate. The spiniform scales of the 

 mouth-tentacles are borne on the edge of a little supplementary plate in a way 

 similar to Ophioglypha. Numerous (9) thorny translucent arm-spines, arranged 

 along the sides of the side arm-plates, which are prominent, and meet nearly or 

 quite above and below. In each interbrachial space two genital openings, which 

 begin close outside the mouth-shield. Lyman ( 53 ). 



Ophiochiton n. g. Disk covered with fine , imbricated scales and small radial 

 shields. Numerous sharp mouth-papillae, with teeth, but no tooth-papillae. Upper 

 and under arm-plates about as broad as long, and separating the side arm-plates, 

 which project slightly and are rather small. Under plates furnished with a me- 

 dian longitudinal ridge. Arm-spines slender and smooth, arranged on the sides of 

 the side arm-plates, near the outer edge. Two long genital openings in each in- 

 terbrachial space. Lyman ( 53 ). 



Ophiogeron n. g. Disk covered by a naked skin. Mouth -angles naked, except a 

 few small teeth on jaw-plate. Under arm-plates small, and with a large tentacle- 

 pore on either side. Side arm-plates somewhat flaring and carrying thorny arm- 

 spines covered with skin. No upper arm-plates. Lyman ( 53 ). 



Ophiolnbes n. g. Disk and arms stout, and covered by a thick skin, which bears 

 grains or stumps, and hides more or less the underlying plates. Arm-spines short, 

 blunt, thorny, covered by thick skin, and arranged on the sides of the side arm- 

 plates , which project but slightly. Long stout mouth-papillae , and teeth ; no 

 tooth-papillae. Jaw-covers large and wide, making a circle by their connecting 

 ends. Arm-plates rather small, but normal, nearly as in Ophiacantha. Two ge- 

 nital openings in each interbrachial space. Lyman ( 53 ). 



Ophiomastus n. g. Disk arched and extremely high, covered with a few large 

 thick plates, among which the primaries are conspicuous for superior size. Arms 

 short, with large thick side arm-plates. First under arm-plate similar to and 

 nearly as large as those beyond. Mouth-papillae arranged in a narrow close-set 

 line; teeth rather slender; no tooth-papillae. Small smooth arm-spines arranged 

 along outer edge of side arm-plates. Two narrow genital openings in each inter- 

 brachial space. Lyman ( 53 ). 



OphiopJiyHum n. g. Disk extremely thin and flat, covered with scales and large 

 radial shields , and bordered by a row of plates, which are movable and attached 

 by their inner margins. Mouth-papillae arranged in a close row; no tooth-papil- 

 lae ; teeth. Arm-spines thin and broad, standing on outer edge of side arm-plate. 

 Two genital openings in each interbrachial space. Lyman ( 53 ). 



Ophioplinthits n. g. Disk smooth and covered by a thin skin bearing irregular 

 delicate scales and radial shields. Genital scales wide and divided in several 

 pieces. Small, blunt, close-set mouth-papillae ; no tooth-papillae ; short angular 

 teeth; very minute, peg-like arm-spines on outer edges of side arm-plates. Se- 

 cond pair of mouth-tentacles and first two pairs of arm-tentacles rising from 

 round pores near the inner end of the under arm-plates ; those beyond are smal- 

 ler, and stand close to the under arm-spine. Arms narrow, cylindrical, and 

 gradually tapering. Two genital openings, running only a part of the way 

 toward the margin. Mouth- frames seen from above, after removing the top of 

 the disk , long and rising in a ridge , so that in the interbrachial space is a wide 

 angle, and in the brachial space a deep trough. Arm-bones long and cylindrical, 

 with only a faint upper furrow. Genital scales long , slender, and cylindrical. 

 Lyman ( 53 ). 



Ophiopyren n. g. Disk granulated. Teeth; no tooth - papillae ; numerous mouth- 

 papillae arranged in a close line. Mouth-frames long and conspicuous. Side 

 mouth-shields small and widely separated by the mouth-shield. Under arm-plates 



Zool. Jahresbericht. 1882. I. 13 



