OPHIUEANS OF THE PHILIPPINE AND ADJACENT WATERS. 119 



by two straight sides, and a convex distal border showing in the 

 middle a more or less marked rounded lobe. The adoral plates are 

 elongated, with the long sides parallel, three or four times as long as 

 broad, and they give off outwardly a narrow process which separates 

 the mouth shield from the first side arm plate. The oral plates are 

 large, triangular, higher than broad. The lateral mouth papillae, 

 three in number, are rather large, elongated, rather narrow, pointed, 

 and very rugose ; the unpaired terminal papilla is larger than those 

 on either side. 



The arms are rather narrow, somewhat rnoniliform, with the seg- 

 ments elongated, and they are more or less incurved ; the upper arm 

 plates are small, triangular, with a rather open proximal angle and 

 a strongly convex distal border; they are almost as long as broad 

 and are separated by a space which is greater than their own length. 



The first under arm plate is rather large, rectangular or trape- 

 zoidal, a little broader than long. The following, which are rather 

 small, are pentagonal, with an obtuse proximal angle bordered by two 

 straight sides, two straight lateral borders, and a rounded distal 

 side which is more or less notched in the middle; they are a little 

 longer than broad, and are separated from the first outward by a 

 rather large interval. The second and the third plates are still of 

 rather large size, but on the following the size diminishes rapidly. 



The side arm plates, which are greatly developed, especially on the 

 dorsal side, project strongly, and they carry at first six rather large, 

 cylindrical, blunt-pointed spines. The first ventral spine is longer 

 than the segment, and the length increases to the last dorsal, which, 

 on the first arm segments, may reach a length of two segments. Their 

 surface is very rugose and may even show very fine and very closely 

 crowded denticulations. 



The single tentacle scale is elongated, spiniform, and pointed, and 

 its length equals about three-quarters of the length of the under arm 

 plate. 



OPHIORIPA NUGATOR, new species. 



Plate 23, figs. 8, 9. 



Locality. — Albatross station 4781. One specimen (Cat. No. 41128, 

 U.S.N.M.) 



Description. — The diameter of the disk is 5 mm. ; the arms, which 

 are rather broad at the base, taper rather rapidly ; they are more or 

 iess contorted, and their total length may be estimated as 15 mm. 



Ths disk is rounded, slightly incised in the interradial spaces. The 

 dorsal surface is covered with large imbricated plates, among which 

 those of the central region, which are very much larger than the 

 others, stand out prominently. These last are unequal in size, and 



