586 THE VOYAGE OF H.M.S.,CHALLENGER. 
21. Asterias (Stolasterias) stichantha, n. sp. (Pl. CVI. figs. 1-4). 
Rays five. R= 158 mm.; 7 = 17 mm. R>9r. Breadth of a ray at the base, 
about 18 mm. 
Rays elongate, broad and robust at the base, tapering gradually to a pointed extremity. 
Abactinal surface of the rays roundly convex and having a subcylindrical appearance 
when viewed from above. Disk small, slightly convex, but not higher than the rays. 
Interbrachial arcs acute. 
The skeletal plates of the rays are disposed with great regularity, and those of the abac- 
tinal surface bear single uniform spinelets. Nine regular longitudinal series of equally 
spaced, isolated spinelets may be counted on the abactinal surface of the rays, the 
spinelets of the outermost series on each side being a shade larger than the others, and 
represent in my opinion a supero-marginal series. The median radial series is not different 
from the others. The spinelets, which are cylindrical, tapering, and pointed, measure 
from 2°5 to 3°5 mm. in length, and are surrounded at the base by one or two circlets of 
rather large, flattened, peculiarly blunt, skin-covered forcipiform pedicellariz, which have 
to a certain extent the appearance of being appressed to a slightly convex elevation sur- 
rounding the base of the spine. Between adjacent wreaths is a space of naked membrane, 
and large isolated forficiform pedicellarize with strong and coarsely denticulate interlocking 
extremities are present here and there. The papulz are in small, compact, isolated groups, 
with seldom more than five or six in each, except upon the disk, where the number is 
rather greater. The infero-marginal plates bear two spinelets, which stand as an obliquely 
placed pair; these spinelets are a little longer than the supero-marginal series, very robust 
at the base and thickly skin-covered, and each bears on its outer side a small tuft of pedi- 
cellarize similar to those above described. ‘The small but distinct space of naked mem- 
brane between the supero-marginal and infero-marginal spines is occupied only by small 
isolated groups of papule and an occasional large forficiform pedicellaria. Between the 
infero-marginal plates and the adambulacral plates is a single series of large isolated 
papulze, one standing between each pair of infero-marginal spines and near the base of the 
innermost spine of the pair. 
The adambulacral plates are very small, and their armature consists of two rather long, 
equal, cylindrical, and slightly tapering spinelets which radiate slightly apart. At the 
base of the ray they measure from 3°5 to 4 mm. in length. Along the margin of the 
furrow, at the base of the innermost spines, are a number of large, elongate, pointed-jawed, 
forficiform pedicellariee with long peduncles.. There may be one to each alternate plate, 
but sometimes they occur more frequently. 
The ambulacral furrows are very wide, and the tube-feet, which have small, fleshy, 
centrally invaginated terminal disks, are quadriserial in their arrangement throughout. 
The madreporiform body, which is rather large and circular in outline, is situated 
about midway between the centre of the disk and the margin; its surface is marked 
