NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 231 



called spines, while in other cases nearly all of the granules are 

 elongated and most of them are really spiniform. 



OPHIACANTHA LAMBDA, new species.a 



Disk 10 mm. in diameter; arms about 60 mm. long. Disk covered 

 by a dense coat of small, elongated granules. Radial shields bare dis- 

 tally, widely separated. Upper arm plates rhombic or triangular, with 

 distal side convex, widely separated. Interbrachial spaces below, less 

 closely covered than disk, with elongated granules. Oral shield very 

 large, wider than long, pointed within, laterally rounded. Genital slits 

 small. Adoral plates L-shaped, meeting within, the short arm of the 

 L about half as long 

 as the other, and 

 separating the oral 

 shield from the first 

 side arm plate. In- 

 ner ends of adoral 

 plates and the oral 

 plates carry a num- 

 ber of granules like 

 those of the disk, 

 but shorter. Oral 

 papillae four on a 

 side, and a large, 

 flat, pointed one at 

 apex of jaw; outer- 

 most papilla much 

 the largest, very 

 wide, truncate. 

 First under arm 

 plate large, wider 

 than long, some- 

 what hexagonal; FIG. 108. OPHIACANTHA LAMBDA. X 5. a, FROM ABOVE; 6, FROM 



succeeding plates 



also wider than long, pentagonal with distal side convex; all are 

 widely separated from each other. Side arm plates large, meeting 

 above and below, each with five smooth pointed arm spines, of which 

 the uppermost is much the longest, nearly equaling three joints. 

 Tentacle scale single, very large, oval, flat, not at all pointed. Color 

 (dried from alcohol), nearly white. 



Locality. Albatross station 4957, off southern Japan, lat. 32 36' 

 N.; long. 132 23' E., 437 fathoms, green-brown mud, fine gray sand, 

 foraminifera, bottom temperature 39.8, 2 specimens. 



a Aappda, signifying L, in reference to the shape of the adoral plates. 



