480 THE VOYAGE OF H.M.S. CHALLENGER. 
fibres: and the interspaces include two or three large spiracula. All the spinelets are 
uniformly protuberant, and that only to a slight degree ; they are rather closely placed, 
and the whole abactinal area is thickly covered with rather fleshy wrinkled skin, presenting 
a somewhat spongy and subpapillose appearance, and a slightly scabrous feeling to the 
touch. ‘he primary meshes are not very distinctly marked out superficially, and the 
hexagons consequently appear to overlap or run into one another in many cases. The 
oscular orifice is small and inconspicuous. 
The ambulacral furrows are broad and more or less petaloid, the closely placed and 
prominent transverse adambulacral spine-combs adding greatly to the appearance of 
breadth. The tube-feet are arranged in quadruple series. The combs of spines forming 
the adambulacral armature are broad, a feature further enhanced by their method of 
arrangement. ach alternate comb has usually two spines less; in this way combs of 
seven to eight spinelets alternate regularly with combs of five. The larger combs radiate 
well over the furrows, whilst the smaller ones, on the other hand, are considerably retired 
from the margin, the innermost spine standing perpendicularly, or even directed slightly 
outward. Hence when seen from above, the smaller combs appear to occupy little more 
than one-half, or at most two-thirds, the space of the larger combs. In the larger combs 
the innermost spine is smaller and shorter than the rest, frequently not more than half 
the length. In the smailer combs the innermost spine is much smaller still, often quite 
aborted and apparently absent. The other spines are nearly equal in length, and both 
combs are uniform with one another in this respect. The combs are thickly webbed, and 
have large and elongate saccular extensions developed over the extremities of the spinelets. 
The mouth-armature resembles that of Retaster verrucosus. The mouth-spines are 
eight to ten in number, four or five on each plate, both series being webbed together, 
and forming a narrow scoop-like fan. The secondary or superficial mouth-spines, one on 
each plate, are thin, cylindrical, not tapering, no longer than the mouth-spines, and 
covered with membrane. 
The actino-lateral spines are of moderate length, reaching up to the margin of the 
test ; they are hidden in membrane, of which a saccular but not indented prolongation 
extends beyond the extremities as a fleshy marginal fringe. The segmental apertures of 
the abactinal chamber are very large and elongate, situated well within the transverse 
combs, and quite hidden thereby. 
Colour in alcohol, purplish grey. 
Locality.—Station 1494. Off Cumberland Bay, Kerguelen Island. January 29, 
1874. Lat. 48° 45’ 0” &., long. 69° 14’ 0” E. Depth 127 fathoms. Volcanie mud. 
Surface temperature 39°°8 Fahy. 
Remarks.—Retaster peregrinator resembles in general form Fetaster verrucosus from 
the Atlantic side of the Strait of Magellan, of which it may be regarded as the representa- 
tive in the Southern Ocean area. The two forms are, however, specifically distinct, and 
