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, cylindrical, 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, 9.5 : 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 
arm-plates were narrower and thinner, and the disk-scales smaller and beset 
with few spines. This species differs from O. 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 chelys Wyv. Tnom., Voyage of the “* Challenger.” Atlantic, Vol. II. 
p. 64, Figs. 16, 17. 
Plate IX. Figs. 239-241. 
Special Marks. — Radial shields widely separated ; along their entire inter- 
brachial margin run large disk-plates. Under arm-plates not swollen. Ten- 
tacle-scales large and flat. Under arm-spine thickened and curved. 
Description of an Individual (Station 84). — Diameter of disk 9mm. Length 
of arm about 85 mm. Width of arm near base 2.8mm. Mouth-papille 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- 
