OPHIURANS OF UNITED STATES NATIONAL MUSEUM. 115 



Fish Hawk station 7285. Feb. 19, 1902. Lat.24 15' 00"; long. 81 47' 30" W.; 

 306 fathoms; s.; temp. 47.5 F. Several specimens (diameter of the disk, 5-12 mm.). 



Fish Hawk station 7286. Feb. 19, 1902. Lat.24 18' 00"; long. 81 47' 45" W.; 

 133 fathoms; s.; temp. 53.5 F. Five specimens (diameter of the disk, 8-12 mm.). 



OPHIOLOGLMUS SECUNDUS, new species. 

 Plate 16, figs. 4-5. 



Albatross station 2666. May 5, 1886. Lat. 30 47' 30" N.; long. 79 49' W.; 

 294 fathoms; gy. s.; temp. 48.3 F. Four specimens. 



Type.C&t. No. 32302, U.S.N.M. 



All the examples are small; in the largest one the diameter of the disk is 6 mm., 

 and the arms are 16 mm. long.; in the others the diameter of the disk ranges between 

 3 and 4 mm. The arms number six in the four specimens. 



The disk is circular or hexagonal with rounded angles. The upper face is 

 covered with extremely thin and transparent plates, which are small, rounded, 

 imbricated, and of a uniform size, both at the center and at the margin, without the 

 slightest indication of primary plates. 



There are radial shields which are not very conspicuous, although notably 

 larger than the adjacent plates; they are triangular, elongated, one and a half times 

 or even twice longer than wide, and broadly separated by four or five rows of plates. 

 The plates of the upper face of the disk extend a little over on the arms, but not so 

 far as in Ophiologimus hexactis H. L. Clark. 



The under face of the disk displays a covering of plates which are identical 

 with those of the upper face and altogether uniform; these plates extend as far as 

 the mouth shield. The genital plates are thin, elongated, and not very apparent. 

 The genital slits are large and broadly open. 



The middle-sized mouth shields have a triangular chief portion and a widened 

 distal lobe, which protrudes more or less into the interradial space; the proximal 

 angle is obtuse, rounded, and limited by two sides also rounded; these shields are 

 almost as long as wide. The adoral plates are narrow and elongated; they are a 

 little widened in their internal part, where they lean against each other along 

 the interradial median line, and they are still more widened outwardly, so as to 

 separate broadly the mouth shield from the first lateral brachial plate. The oral 

 plates are triangular and very high. The oral papilla3, which amount to seven or 

 eight on each side, are very small, narrow, and conical: however, the two external 

 papillae, which correspond to the oral tentacular pore, are somewhat larger: the odd 

 tooth papilla is a little more elongated than the others. Another somewhat elon- 

 gated and conical papilla starts from the angle of the adoral plate and the first 

 under brachial plate, and is directed toward the mouth. 



The arms are fairly narrow. The upper brachial plates, which are middle- 

 sized, are triangular, with a proximal angle and a convex distal side; they are 

 almost as long as wide and separated from one another from the bases of the arms. 



The first under brachial plate is rather large, lozenge-shaped, and a little wider 

 than long, with a fairly open proximal angle, which is limited by two straight sides, 

 and a rounded distal angle, also limited by two straight sides. The succeed- 

 ing plates become much longer than wide, with a proximal angle, which is first 



