96 
The supramarginals, of which there are 50 from the tip of one 
arm to the tip of the next (or twenty-five on each side of an arm), 
diminish in breadth as the apex is approached, but less markedly 
so than in M. arcuatus Sladen. The breadth now exceeds the 
leneth. | 
Valvate pedicellariz are few, but in fair number irregularly scat- 
tered on the abactinal surface. The madreporite is rather large, 
about 23 times the diameter of the neighbouring plates ; is six- rayed ; 
and lies near the centre of the disc, from which it is separated by its 
own diameter, whilst it is about six of its diameters from’ the 
margin. 
The marginals are covered with low rounded tubercles, of which — 
those on the edges of the plates are rather larger (not smaller as in 
M. arcuatus) than those on the face. 
A few large valvate pedicellarize occur on the supramarginals, 
varying in number on the five “ sides” of the starfish (7.e., between 
tip and tip of the two | : on two sides, none; on the third side. 
1; on the fourth side, 3; on the fifth side, 5. The inframarginals 
alternate with the supramarginals, except the odd interbrachial 
plate, and sometimes the one on each side of it. I see no pedicel- 
larize on these plates. 
The adambulacrals carry 4 longitudinal rows of stout, prismatic, 
round-topped spines; the innermost row, overhanging the groove, 
consists of 4 or 5 spines: if the former, one is much stouter than the 
other three. They stand closely side by side, looking like a thick- 
toothed comb, and have brown tips. The second row contains 3 
or 4, the third only 3 spines. The 3 or 4 of the outermost row are, as 
usual, much smaller than the preceding, and only a little larger than 
those on the actinal plates. Sometimes this row is irregular, so that 
an imperfect fifth row is apparently present. 
The angle of the mouth bears on the margin about 16 to 18 stout 
prismatic spines, similar to and of the same length as the mnermost 
adambulacrals, directed towards the centre. On the actinal surface 
of each of the angle-pieces is a row of 6 or 7 similar but rather smaller 
spines, like those of the second row but slightly stouter; and also a 
few small tubercles are present. The actinal plates are continued 
from the interbrachial areas along the arm to the level of the fifth 
or fourth marginal from the tip. All these plates are similar to those 
on the upper surface, and I see no pedicellariz. 
Locality.—Off Oamaru, on shell gravel, at a depth of 25-30 fathoms. 
Remarks.—The leading difference between this starfish and Aster- 
odon miliaris, to which it bears a considerable superficial resemblance, 
is in the character of the oral armature ; for, in place of the two ‘re- 
flexed dental spines at each oral angle, this species bears a number 
of small spines similar to those of the adambulacrals. 
I have had’ access only to Siaden’s description of MM. arcuatus, 
of which a single individual was during the “ Challenger” expedi- 
