274 BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



on each side of jaw, there are often to be found one or two small 

 blunt tubercles, which may be regarded as rudimentary oral papillae. 

 First under arm plate wider than long; second and third about 

 square; succeeding plates more or less indistinct, each with a deep 

 median notch in distal margin. Side arm plates small and narrow; 

 each plate carries four slender, acute, thorny, skin-covered spines; 

 next to uppermost longest and equal to two joints. Tentacle pores 

 large but tentacle scales none. Color (dried from alcohol), yellow 

 brown. 



Locality. Albatross station 3704, off Seno Umi, Honshu Island, 

 Japan, 94 to 150 fathoms, fine volcanic sand, 1 specimen. 



Type. Cut. No. 25713, U.S.N.M., from station 3704. 



This unique specimen, one of the most interesting in the whole col- 

 lection, is unusually well preserved, so that its characters are easily 

 made out. Although it looks more like an OpJiiomyxa than an 

 Ophiobyrsa, on account of the shorter and wider arms, its real rela- 

 tionships are probably nearer the latter genus. 



OPHIOCYNODUS, new genus. 



Disk covered with naked skin. Radial shields, upper arm plates 

 and tentacle scales wanting. Teeth, tooth papillae and oral papillae 

 alike, spiniform, rough at tip. 



Type-species. Ophiocynodus corynetes. 



This genus presents a really remarkable combination of characters, 

 for while its general appearance resembles Opliiomyxa, the mouth 

 parts and the absence of radial shields and upper arm plates show 

 it is no near relative of that group. 



OPHIOCYNODUS CORYNETES, new species.6 



Disk 30 mm. in diameter; arms about 160 mm. long. Disk covered 

 with a naked skin on which are scattered some calcareous grains. 

 Radial shields wanting, but expanded upper ends of genital plates 

 show through the skin at base of arm. No upper arm plates. Inter- 

 brachial spaces below, naked. Oral shields small, longer than wide, 

 wider within than without. Adoral plates large, three times as long 

 as wide; oral plates large. Teeth, tooth papillae, and oral papillae 

 all alike, rather numerous, spiniform and rough at tip; upper teeth 

 largest; distal oral papillae smallest. Under arm plates large, dis- 

 tinct, except first two longer than wide. Side arm plates small, 

 each with three subequal spines, nearly equal. to two joints; upper- 

 most spine pointed, lowest club-shaped with a marked swelling at 

 tip; middle spine intermediate; all spines are rough at tip, and more 



a Ofao and Ktjvddotjf, signifying canine tooth, in reference to the epiniform teeth and 

 oral papillae. 



& KopuvrjTrjf, signifying a club-bearer in reference to the form of the lower arm 

 spines. 



