NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 177 



widely separated, nearly three times as long as wide. Upper arm 

 plates as long as broad or nearly so, the distal margin very convex 

 while the proximal half is three-sided with more or less, or almost 

 completely, obliterated angles; supplementary plates rather large 

 and, as described above, provided with minute secondary plates 

 along their distal border. Interbrachial space below very closely 

 covered with minute scales. Oral shields rounded triangular, or 

 arrow-head shaped, somewhat longer than wide, particularly in the 

 young (in fig. 79e the shield is too wide). Ad oral plates, long tri- 

 angular, hardly meeting within. Jaws short, with four to six oral 

 papillae which are rather long, flat and rounded in the young, but 

 become thick and truncate in the adult. First under arm plate 

 somewhat pentagonal, of moderate size; succeeding plates oblong 

 or somewhat pentagonal, longer than wide, broadly in contact. 

 Side arm plates small, each with three thick, blunt spines, of which 

 either the middle or lowest is the longest, and about equals the joint. 

 Tentacle scale single, very large, elliptical, (^olor (dried from alco- 

 hol), disk, yellowish with an irregular network of purplish-brown 

 lines; arms grayish, banded with dull ])urple; the relative amount 

 of yellow and purple on the tlisk is variable, as is also the number of 

 bands on the arms and their distance from each other. 



Localities. — Albatross station 3758, off Suno Saki, Honshu Island, 

 Japan, 52 to 73 fathoms, blue clay, rocks, 1 specimen; station 4875, 

 Korea Strait, lat. 34° 19' N.; long. 130° 9' E., 59 fathoms, fine gray 

 sand, broken shells, bottom temperature 62.1°, 1 specimen; station 

 4879, Korea Strait, lat. 34° 17' N.; long. 130° 15' E., 59 fathoms, 

 fine gray sand, broken shells, bottom temperature 62.1°, 1 specimen; 

 off Japan, station ?, 1 specimen. 



Type.— Cut. No. 25715, U.S.N.M., from off Japan. 



The specimens with six arms range from 2.5 to 4.5 mm. in disk 

 diameter. Specimens of Ophionereis porrecta of the same size have 

 only five arms. It is of course possible that these six-armed speci- 

 mens tlo not belong to the same species as the larger five-armed one 

 which I have taken as the type of didi/disca, but their resemblances 

 otherwise are so close I am satisfied of their identity. 



OPHIODORIS PERICALLES, new species." 



Disk 11 nun. in diameter; arms about 110 mm. long. Disk cov- 

 ered by a close smooth coat of fine scales, distinctly larger along mar- 

 gin, in interbrachial areas. Radial shields small, witlely separated, 

 about twice as long as wide; distal to them, and extending down- 

 ward on the genital scales, are a number of minute spinelets, the 



a IlepiKaXXTjc, t^i^nifying very pretty, in reference to the form and markings. 

 34916°— Bull. 75—11 12 



