512 THE VOYAGE OF H.M.S. CHALLENGER. 
great number of small spiracula not quite so closely placed as those on the disk, and not 
arranged in lines. 
The ambulacral furrows are rather widely petaloid, and rapidly constricted at the 
extremity. The armature of the adambulacral plates consists of three short spines, nearly 
uniform in length, pointed, and covered with a membrane expanded into a lanceolate 
shape, but with no terminal saccular prolongation. Each series of spines is placed diago- 
nally upon its plate, or oblique to the line of the furrow. The aperture-papille are large 
and broadly subspatulate or even subrhomboid, expanded somewhat obliquely, the pedicle 
seeming to be attached rather on one side. The mouth-plates are rather broad, prominent 
aborally, and have five or six short mouth-spines attached to the lateral aliform extensions, 
and directed horizontally. Two short, robust, subconical secondary mouth-spines are borne 
on the superficies of each plate—one near the adoral extremity, and the other, which is 
thickest, placed midway between this spine and the aboral extremity of the mouth- 
plate. 
The actino-lateral spines are long and well spaced, about forty on each side of a furrow, 
the eleventh or twelfth from the mouth being longest. The spines within the disk do not 
quite meet in the median interradial line, and those along the outer third of the ray 
diminish in length very rapidly; they are, however, rather irregular in their length 
throughout, which gives a ragged appearance to the fringe. The spines are pointed at 
their extremities, and the web is very slightly indented between. 
Colour in alcohol, yellowish grey. 
Locality.—Station 158. South of Australia, 1099 miles south-west of Cape Otway. 
March 7, 1874. Lat. 50° 1’ 0” S., long. 123° 4’ 0” K. Depth 1800 fathoms. Globigerina 
ooze. Bottom temperature 33°°5 Fahr.; surface temperature 45°°0 Fahr. 
Remarks.—Hymenaster crucifer is distinguished, as its name implies, by the peculiar 
eross-like markings formed by the paxille-crowns. A further characteristic feature is 
furnished by the general structure of the supradorsal membrane and the lineal disposition 
of the spiracula. 
13. Hymenaster anomalus, Sladen (Pl. LXXXIX. figs. 3 and 4; Pl. XCI. figs. 4-6). 
Hymenaster anomalus, Sladen, 1882, Journ. Linn. Soc. Lond. (Zool.), vol. xvi. p. 228. 
Marginal contour stellato-pentagonal. Interbrachial ares wide and rather sharply 
and angularly indented, the minor radius being in the proportion of 63 to 65 per cent. 
R=15 mm.; r=9°5 mm., approximately. Rays subtriangular in outline, and tapering 
to a fine extremity. Form very depressed, only slightly elevated in the centre of the 
disk. Marginal fringe quite inconspicuous when seen from above. 
The supradorsal membrane is furnished with uniformly thick fibrous bands, closely 
reticulated, the network exhibiting a certain incipient regularity of construction. The 
