NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 249 

 OPHIOPHRURA, new genus.a 



Disk covered with a smooth coat of fine scales, entirely concealing 

 the radial shields; oral tentacle scales very long and conspicuous; 

 tentacle scales of arm numerous, three or four guarding each pore; 

 otherwise as in Ophiacantha. 



Type-species. Ophiophrura liodisca. 



Although obviously related to Ophiacanfha, the following species 

 is so well characterized it seems to me best to make it the type of a 

 new genus. The smooth, finely scaled disk, without an external 

 hint of radial shields, looks very different from any OpJiiacantha I 

 have seen, while the very long spine-like scales at the distal ends of 

 the mouth slits and the numerous tentacle scales give the oral surface 

 an equally characteristic appearance. 



FIG. 121. OPHIOPHKURA LIODISCA. x 6. , FROM ABOVE; b, FROM BELOW; c, SIDE VIEW OF THREE ARM 



JOINTS NEAR DISK. 



OPHIOPHRURA LIODISCA, new species.^ 



Disk 8 mm. in diameter; arms about 20 to 25 mm. long, probably. 

 Disk covered with a smooth coat of very fine scales which entirely 

 conceal the radial shields. Upper arm plates rhomboidal with distal 

 angle rounded, about as long as wide; basal ones nearly or quite in 

 contact, but middle and distal ones well separated. Interbrachial 

 spaces below covered like disk by fine scales. Genital slits large. 

 Oral shields pentagonal, nearly as long as wide, disto-lateral sides 

 concave. Adoral plates narrow and meeting within, broad without 

 and separating oral shield from first side arm plate; oral plates long 

 and narrow. Oral papillsB numerous, nine or ten on a side, of which 



a "0<f>to and (frpouph, signifying a guard, in reference to the numerous tentacle scales. 

 b Aioc, signifying smooth, and diaxof t signifying disk, in reference to the absence 

 of all spines and granules from the disk. 



