10 66 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
the whole of the abactinal and actinal surfaces and marginal plates are covered with variously sized 
spiniform granules, each invested with a soft, thick, and pulpy membrane which completely hides the 
granules, giving the appearance of a crowded, soft, warty, irregular, granulation. These fleshy 
granules are round- or flat-topped, and so crowded that they press each other out of shape. They 
completely hide the outline of the abactinal plates. Scattered over abactinal surface are many short, 
stout, sharp, erect, conical spines, giving the whole surface a bristling appearance. The largest are 
2 mm. long, and they decrease in size toward the margin. Scattered among them are many inter- 
mediate, sharp, conical tubercles of several sizes, evidently specializations of the immersed granules. 
The pulpy membrane rises upon the base of the spines, but is not evident toward the tip. Spines are 
arranged in 2 or 3 irregular rows on ray, and decrease very irregularly in size toward its extremity. 
Over all the disk except a very limited and narrow interradial region long, conspicuous papulae emerge 
from the reticulated covering. They are scattered around the plates; absent from rays. On interradial 
areas of disk are a few large 2-jawed upright pedicellarite. These are sunken in special pits, have 
broad, even, rounded, often notched, spatulate jaws, which, however, possess no especial depression 
into which they fit when opened. 
Marginal plates are large, but not conspicuous. The 2 series correspond in number and are 
opposite. Superomarginals, 15 in number from median interradial line to extremity of ray, are 
confined to side wall of body in interbrachial arc, but encroach more and more upon abactinal areas 
as they proceed along the ray. On outer part of ray their breadth very nearly equals height. In 
interbrachial arc the length is a trifle greater than height (or width). Transverse sutures and that 
separating the 2 series are easily seen. The line of demarkation between the marginal and abactinal 
plates is not clearly evident. On disk the superomarginals bear 3 stout, rigid, sharp, conical spines, 
stouter than those of the dorsal integument, disposed in a transverse series on a median tumid portion of 
the plate. At base of ray these become reduced to 2, and on outer portion of ray to but one, which stands 
on a sort of boss where the lateral and dorsal superficies of the plate meet. First superomarginal 
usually has slightly shorter spines, and 3 or 4 of them are grouped in the center of plate, with a 
number of subsidiary conical granules surrounding them. A marginal series of rather regular, 4-sided 
to subcircular flattish, fleshy granules borders each plate — save the upper edge. Within this is a second 
series of larger spherical to subconical granules, less regular, surrounding the base of the tumidity 
which bears the spines. On outer portion of ray the transverse portions of second series of granules 
are absent. First and second plate usually have a pedicellaria similar to those of abactinal surface near 
the middle of the lower side just above the peripheral row of granules. 
On disk the inferomarginals are slightly larger than corresponding superomarginals, are quadrate, 
about as broad as high, and form an evenly curved margin to actinal area, upon which they encroach. 
They are tumid like the superomarginals, the tumidity becoming more pronounced on ray, on the 
proximal plates of which are 2 (usually 3 on innermost plate of ray proper) rigid spines, similar to 
those of superomarginals, and similarly placed. On outer third or half of the ray these are reduced to 
a single spine. On first 3 inferomarginals there are 7 shorter spines, with several enlarged granules, 
scattered in an irregular quadrate group. Fleshy granules, like those of superomarginals, cover the 
remaining surface of the plates. The inner or lower edge of the plates is not evident superficially, 
the granules being continuous with those of actinal interradial areas. In one interradius there is a 
small pedicellaria, like those described for superomarginals, situated near the upper border of each 
of the 2 median inferomarginals. 
Ambulacral furrow rather narrow. Outlines of adambulacral plates not evident superficially on 
account of the fleshy granules. Plates are slightly longer than wide, with a convex margin to furrow. 
Furrow spines are 6 on first plate, 5 on second, and 4 or 3 on the rest. They are long, stout, strongly 
compressed, with broad subtruncate or rounded tips. They resemble broad chisel or narrow hatchet- 
blades in shape, and become thinner toward the tip. Where there are 4 spines the aboral is shortest, 
and varies much in shape, resembling usually a wedge. The other 3 are subequal, or the median 
slightly the longest. Often a spine appears as if partially twisted on its long axis, or the broad spatulate 
blade may be a trifle concave on one face like a scoop. The 2 lateral members are usually broader at 
the tip than the median. In the middle of the actinal surface of plate stands a solitary, remarkably 
heavy, rigid, upright spine, shorter than furrow spines. Its base is cylindrical, but the end flares 
more or less, and the outer aboral face is concave like a gouge; the tip is rounded, subacute, or blunt. 
Frequently the tip appears somewhat 3-sided, one side concave, and the others flat or slightly rounded. 
