REPORT ON THE ASTEROIDEA. 273 
of the ray than by the regular curve of the side as a whole. Margin thick and vertical, 
equally rounded actinally and abactinally. Actinal area plane or slightly concave, undu- 
lating, more or less flexible, and capable of some inflation ; a slight sulcus usually defined 
along the median interradial line. 
The whole abactinal area is covered with small, recular, polygonal tabula, which 
diminish in size as they approach the margin (where they are very small) ; they are also 
smaller in the central region of the disk and along the edge of the interradial sulcus than 
in the median radial area and on the actual floor of the sulcus. The larger tabula in the 
radial areas, which are more or less elevated or paxilliform, are comparatively widely 
spaced, exposing the papul, of which there are about six round each tabulum, separated 
from one another by the stellate prolongations of the basal portion of the plates. The 
paxillee consist of a hexagonal, rhomboid, or polygonal tabulum, slightly raised and 
faintly convex in the radial regions, where the paxille: are widely spaced. The tabulum 
is covered with coarse, low, and almost truncate granules, and the margin is surrounded 
by a series of thin lamelliform papille or flattened granules, which have a striking appear- 
ance as compared with other species (see Pl. XLIX. fig. 1). A small excavate pedicellaria 
with two rather broad jaws and associated pit is present on some of the tabula, and 
appears to be always placed at the margin of the tabulum, some of the neighbouring 
granules being scooped away as it were for its reception. 
The supero-marginal plates, which are seventeen in number, counting from the median 
interradial line to the extremity, form a well-defined and nearly uniformly broad border to 
the abactinal area. The plates near the interradial line have their length and breadth 
subequal, the length being perhaps slightly in excess; as they proceed along the 
ray, however, the length diminishes step by step, until at the extremity the breadth is 
fully twice as great as the length. The plates are distinctly tumid. The lateral surface 
of the plates is covered with very small, uniform, crowded granules, but on the abactinal 
area of the plate there is a large naked quadrangular space which occupies nearly the 
whole of that surface, being separated from the margin only by two (or rarely three) rows 
of the small granules. The majority of the plates bear one, or occasionally two, small 
pedicellarize placed at the edge of the naked space. 
The infero-marginal plates correspond to the superior series, and are, like them, 
covered with small crowded granules, excepting, however, a small circular area on the 
actinal surface of each plate, which is naked. Nearly all the infero-marginal plates bear 
one of the small excavate pedicellariw similar to those on the supero-marginal plates; a 
few plates bear two. The pedicellarise appear to be invariably placed close to one of the 
margins of the plate. 
The adambulacral plates are slightly broader than long, and their armature consists of a 
marginal series of six short, subequal spinelets, excepting the adoral spine of the series, which 
issmaller. The spinelets are thick and subprismatic or quadrangular in section, and have a 
(ZOOL. CHALL, EXP.—PART LI.—1888.) 35 
