152 BULLETIN OF THE 



more blunt and flat. Mouth-shields small, as long as broad, with an irregular 

 outline ; outer margin more or less thickened and turned downward ; length 

 to breadth 2 : 2. Side mouth-shields broad and thick, and closely joined to 

 surrounding parts. Under arm-plates broader than long, broader without than 

 within, separated by slight transverse depressions ; outer edge thickened, espe- 

 cially at its middle point. Midway on the arm, they are wide pentagonal, 

 with an obtuse angle inward, and the outer edge not thickened. Side arm- 

 plates slightly projecting, meeting near base of arm narrowly below and 

 scarcely or not at all above. Upper arm-plates separated by transverse creases, 

 thick, wider than long ; widest without, where they are bounded by a gentle 

 curve ; inner side making a deep irregular curve. Disk (in alcohol) thick, 

 rising well above the arms, with a deep constriction and furrow in each inter- 

 brachial space. On margin of disk and along outer interbrachial edge of radial 

 shields lie three or four wide plates larger than the rest, which are coarse, 

 irregular, overlapping scales, beset with short, stout, smooth, often club-ended 

 spines, which are found also on edge of disk over the arms. Radial shields 

 pear-seed shaped, with point inward, sunken, outer end rounded, separated 

 ■widely by a broad wedge of scales ; length to breadth 4 : 1.8. Near base of 

 arm eight stout, glassy, blunt, cylindi-ical, very thorny spines, of which the 

 under are nearly as long as the upper ; lengths to that of an arm-joint 2, 3.8, 

 3, 2.8, 2.8, 2.8, 2.5, 2.5 : 1.7. Two thirds out on the arm there are only four 

 spines, of which the second is much the longest, 5.5 mm. Two tentacle-scales 

 on the first pore, one on the others ; stout, pointed, flattened, cloven or jagged 

 on the edges ; farther out they take on the form of stout, very thorny spines. 

 Color in alcohol, dull gray. 



A smaller specimen with a disk of 10 mm. varied little, except that the upper 

 axm-plates were narrower and thinner, and the disk-scales smaller and beset 

 with few spines. This species difl'ers from 0. plicata in the cloven or thorny 

 tentacle-scales and in the greater number of arm-spines. 



Station 146, 1375 fathoms, 3 specimens. 



Ophiomitra chelys. 



Ophiacantha cMys "Wyv. TiiOM., Voyage of the " Challenger," Atlantic, Vol. II. 



p. 64, Figs. 16, 17. 



Plate IX. riRS. 239-241. 



Special Marks. — Radial shields widely separated ; along their entire inter- 

 brachial margin run large disk-jdates. Under arm-plates not swollen. Ten- 

 tacle-scales large and flat. Under arm-spine thickened and curved. 



Description of an hulividual (Station 84). — Diameter of disk 9 mm. Length 

 of arm about 85 mm. Widtli of arm near l)ase 2.8 mm. Mouth-papilla) usually 

 eleven to each angle, of which the central one within is wide and flat ; the three 

 next on either side are stout and pointed, and the outer ones are irregular, 

 compressed, and sometimes broken. Teeth similar in shape to the odd inner- 



