34 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



only y3 the length of the arm segment. Median spine slightly the longest ; 

 upper spine heaviest and blunt. Supplementary arm plates small and tri- 

 angular, about i/io the size of the upper arm plate; inner margin concave, 

 distal and outer margins convex. The supplementary plate is inserted 

 under the upper and proximal side arm plates and overlaps the distal side 

 arm plate. 



Oral shields triangular, about as long as broad, inner margins almost 

 straight. Adoral plates triangular, broader than long, widest distally, 

 meeting within, inner margin slightly concave, other margins straight or 

 slightly concave. Jaws small, triangular. Four oral papillae, about equal 

 in length, on a side. Outermost largest, flat, longer than broad, cutting 

 margin rounded. Inner 3 papillae narrow, flat, longer than broad, bluntly 

 pointed ; inner pair heaviest. Distal to the outer papillae is the first ten- 

 tacle scale, set deep in the mouth, which might easily be taken for an oral 

 papilla. Four broad teeth of equal length, cutting margins convex. 



Interbrachial spaces below covered with unequal, overlapping, crowd- 

 ed scales. The largest scales are centrally located ; those along the genital 

 slits are smaller and crowded so only a portion of the scales are visible. 

 Genital slits short, equal in length to 2 arm segments. First under arm 

 plate small, longer than broad, distal margin convex. Second and suc- 

 ceeding plates large, octagonal basally, triangular distally, longer than 

 wide; proximal lateral margins straight, lateral margins concave, distal 

 margins broadly convex. Plates in contact basally, separated distally by 

 the side arm plates. One large, oval tentacle scale, longer than wide, not 

 quite half the length of the under arm plate, attached to the side arm 

 plate. 



Color. — Dried from alcohol, disk white with dark gray circles at the 

 arm base. Arms dark gray with irregularly spaced white and light gray 

 bands. Under side white with irregular gray bands on the arms. Two of 

 the paratypes differ by having the disk uniformly mottled with white, 

 light and dark gray. Arms irregularly banded with white, light and dark 

 gray. Under side white with several gray bands on the arms. 



Types. — Holotype, AHF no. 22; 3 paratypes. 



Type locality. — Station 287-34, 10-15 fms., Cerros Island, Lower 

 California, Mexico, March 10, 1934. 



Remarks. — This species differs from Ophionereis annulata (Le 

 Conte) of equal size in its coarser disk scaling, lack of genital papillae, 

 arm length twice the disk diameter, and exceedingly small supplementary 

 plates. From the young of Ophionereis eurybrachiplax H. L. Clark, it 



