NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 



29 



square millimeter; those at center of disk are longer and more like 

 spinelets than those near margin. Radial shields entirely concealed. 

 Upper arm plates triangular with proximal angle more or less trun- 

 cated, according to amount of contact between them. Interbrachial 

 spaces below covered with papilla-like granules, which become spine- 

 lets near and around oral shields and on oral plates; these spinelets 

 are very little larger than those at center of disk above. Oral shields 

 ellipsoidal, wider than long. Adoral plates rather small, much 

 longer than wide, widest distally, their outlines more or less obscured 

 by spinelets. Oral papillae four or five on each side with often an infra- 

 dental one in addition; 

 outermost very much 

 the widest. Teeth four 

 or five, not peculiar. 

 First under arm plate 

 much smaller than sec- 

 ond, distinctly wider 

 than long; second and 

 succeeding plates more 

 or less pentagonal with 

 a wide proximal angle; 

 seventh and succeeding 

 plates usually wider 

 than long and widely 

 separated from each 

 other; those preceding 

 the seventh are often 

 longer than wide and 

 only slightly or scarcely 

 separated from each 

 other. Side arm plates 

 rather large, meeting 



slightly above and more FIG. 4. OPHIOCONIS PAPILLATA. X6. a, FROM ABOVE; b, FKOM 



or less broadly below; 



each plate carries six or seven long smooth, rather blunt, hollow 



spines, the uppermost or next to it, the longest, and, at base of 



arm, equalling or exceeding two joints. Tentacle scale single, 



very large, about as wide as long. Color (dried from alcohol), 



very pale fawn or yellowish-brown; beneath and arm spines, nearly 



white. 



Localities. Albatross station 2842, off Aleutian Islands, lat. 54 

 15' N. ; long. 166 3' W., 72 fathoms, pebbles, bottom temperature 41, 

 ten specimens; station 3315, Bering Sea, lat. 54 2' 40" N.; long. 

 166 42' W., 277 fathoms, green mud, sand, bottom temperature 

 38.5, 1 specimen; station 3331, Bering Sea, lat. 54 1' 40" N.; long. 



