REPORT ON THE ASTEROIDEA. 67 
Their margin towards the furrow is straight, or very faintly convex. The armature con- 
sists of :—(1.) A furrow series of twelve short, cylindrical, papilliform spinelets, the median 
ones slightly longer than the others, slightly compressed laterally, but not square in 
section, standing parallel to one another, and forming a long but low, straight comb. The 
longest do not exceed 2 mm. in length. (2.) On the actinal surface of the plate, and close 
behind the marginal series, is a straight row of seven or eight short, subequal, papilliform 
spinelets, which are more widely spaced than the furrow series, and are also more robust, 
but not more than half their length. This series is closely pressed against the furrow 
series, and the spinelets in both are enveloped in membrane, those in the outer series being 
especially papilliform in their appearance. Along the outer margin of the plate is another 
lineal series of seven or eight small, equal, papilliform granules ; and these in consequence 
of the narrowness of the plate are very near to the series above described, but separated 
by a well-defined though very narrow naked space. No other spines, granules, or pedi- 
cellarize are present. 
On the outer third of the ray there is a slightly enlarged spinelet on the actinal sur- 
face of the plate, usually situate in the first actinal series, which is longer than any of the 
other spinelets on the plate and more robust, and sometimes equal in size to the spines on 
the marginal plates. There is no trace whatever of its presence on the plates on the inner 
half of the ray. 
The mouth-plates are large and conspicuous, the united pair being elongately oval, and 
prominently convex actinally. They protrude far over the actinostome, and as seen with 
their armature reflected perpendicularly, have a peculiar sagittiform outline. The arma- 
ture consists of a marginal series of about fourteen short, compressed, papilliform spinelets 
on each plate, all standing parallel, and capable of being directed perpendicularly to the 
plane of the actinal surface; the inner spines forming a wedge-shaped group, and the 
outer seven appearing, to a certain extent, like an independent semicircular series. On 
the actinal surface of the plate are numerous, irregularly disposed, small, papilliform 
spinelets, appearing more or less clavate in consequence of their membranous investment, 
and nearly subequal in length, except two or three larger ones at the extreme inner end 
of the mouth-angle, placed close to the marginal series of true mouth-spines, and contri- 
buting with them to the formation of the wedge-shaped group above mentioned. 
The actinal interradial areas, though small, are well developed, extend as far as the fifth 
adambulacral plate, and contain numerous intermediate plates disposed in regular series 
between the adambulacral and marginal plates. The plates bear groups of small papilliform 
spinelets, which are remarkable from the fact that each bears centrally a conspicuous 
pedicellarian apparatus, usually formed of four thickened and enlarged spinelets, the other 
spinelets of the plate or paxille being very much smaller, and forming a marginal 
surrounding series. 
The anal aperture is subcentral, but indistinct. 
