ECHINODEBMS FEOM WEST AUSTRALIA. 245 
Marginal plates very distinct, the upper series forming a very evident boun- 
dary to the abactinal surface o£ the arm. Intermarginal papulfe numerous. 
At the base of each arm a carinal series of plates is evident and one lateral 
series on each side, but on most of the abactinal surface of each arm, as well 
as on the disk, there is no definite arrangement of the plates evident.' Most 
of the iibactinal and superomarginal plates carry spinelets and minute pedi- 
cellarife. The latter are scattered and not very numerous. The spinelets are 
of two sorts: nearly cylindrical very blunt ones about 'SO-'TS mm. long and 
the diameter one-third to one-half as much ; and stout, markedly conically 
capitate spinelets 1-1"5 mm. long and about one millimetre in diameter ; on 
the marginal plates these heavy spinelets are conical rather than capitate^ 
There is never more than one of the stout spinelets on a plate, but one finds on 
each side of it, usually, 1-3 of the more slender little spinelets ; occasionally 
the stout spinelet is solitary. On the more conspicuous abactinal plates the 
spinelets form transverse series, sometimes without any large one at the middle. 
Madreporite 2 or 3 mm. from the disk margin, small, scarcely 2 mm. in 
diameter, elevated and surrounded by a circlet of 15-20 small spinelets. 
Inferomarginal plates about 28, each with a stout spine, tarely accom- 
panied by a single much smaller one ; distall}'^ the spines are low, blunt^ 
conicall}^, but proximally they are flattened and the tips are chisel-like, or 
deeply channelled on the upper side, or divided into 2 or 3 very short 
branches. These proximal spines are about 2 mm. long with the tip a 
millimetre or more wide. Actinolateral spines in two series continuing 
nearly to tip of ray ; at base of arm there seem to be two series of actino- 
lateral plates, but it is hard to determine how far out on the arm they are 
continued ; the spines are similar to those on the inferomargin.il plates, biit 
are smaller; there is seldom more than one to a plate. Adambulacral spines 
about 2 mm. long, flat, blunt, and rounded, or a little widened at tip, in two 
regular crowded series ; the spines of the outer series are only a little, if 
any, larger than those next the furrow. Oral plates, each with three spines 
of which the distal is smallest and most like the adambulacral spines, while 
the most jDroximal is 3 mm. or more long and very flat and chisel-like. 
Tube-feet crowded, in four series. Pedicellarias are very few on the actinal 
surface; here and there are scattered minute forcipiform pedicellarise, and 
near the base of the ray careful search reveals a few small forfieiform pedi- 
cellarise, with short, erect jaws and no stalk ; they are about as wide as long. 
Colour, of dry specimen, dull yellowish-grey. 
One specimen dredged at Garden Island, near Fremantle. 
In view of the confusion already existing in the genus Uniopliora, it may 
seem of doubtful utility to describe a new species based on a single speci- 
men, but after examining a considerable number of Uniophoras from South 
Australia, representing at least two species and perhaps more, I am satisfied 
that this West Australian form is at least distinct from any of those hitherto 
