454 THE VOYAGE OF H.M.S. CHALLENGER. 
Young Phase.—I have referred a small example of Solaster, which measures R= 20 
mm., from the same locality to this species. It is figured on Pl. LXX. Although at 
first sight this juvenile appears to differ considerably from the adult, I feel little doubt 
that the differences are only due to age. The number of rays is the same. The paxille 
are relatively larger and more distinctly spaced than in the adult. In the armature of 
the adambulacral plates there are only three spinelets in the furrow series on the plates 
near the mouth, and only two along the ray; the transverse lineal series on the actinal 
surface of the plates consists of three robust spinelets. The infero-marginal paxillz form 
a conspicuous border on the actinal surface, similar to what has been observed in the 
adult, and the actinal interradial areas have a similar spinose character. The armature of 
the mouth-plates consists of a marginal series of eight spinelets, the innermost one being 
remarkable for its size and the capacious membranous sac with which it is invested. On 
the actinal surface of each plate is one large robust spinelet, and further back on the plate 
two or three smaller ones. 
Remarks.—This species is very closely related to Solaster endeca, but may be dis- 
tinguished by the form and character of the paxille, by the large actinal interradial 
areas, by the broad band of infero-marginal paxillee, and by the character of the armature 
of the adambulacral plates. 
3. Solaster regularis, n. sp. (Pl. LXX. fig. 1; Pl. LXXII. figs. 5 and 6). 
Rays eight. R = 90 to100mm.; r= 20mm. R= 45to5r. Breadth of a ray 
at the base 14 mm. 
The disk is high and convex. The rays are long, tapering, and attenuate towards the 
extremity ; in the present condition of the specimen all are curled over on the abactinal 
surface. Interbrachial arcs acute. 
The abactinal surface is beset with very short, rather broad, stumpy paxille, the 
crown composed of six to ten very short tapering spinelets, bi- or tri-dentate at the 
extremity, and their bases imbedded in a membranous mass, which envelops the whole 
basal part of the paxilla. The paxille are widely spaced upon the disk, and numerous 
large papulee occupy the interspaces. Along the rays the paxillae become much smaller 
and more numerous. No definite order of arrangement is discernible, although a slight 
tendency to lineal disposition may be made out along the sides of the rays. 
There is a single series of conspicuous marginal plates, on which a thin elevated keel 
is developed, surmounted by a flattened comb of short robust spinelets, about ten to 
twenty in each, resembling enlarged compressed paxille, the long axis being placed at 
right angles to the median line of the ray. The combs are widely spaced, and about 
forty-two are present between the median interradial line and the extremity. I believe 
these to be the infero-marginal plates; and what I take to be the representatives of the 
