94 
Heads and Oamaru, at depths of 18 to 44 fathoms, a considerable 
number were obtained by me in 1899 during trips in s.s. “ Doto” 
and “ Plucky ” in the same locality. [Also, Nelson, Wellington (F.) ; 
Pegasus Bay, and Stewart Island (O.U.M.).] 
It was first recorded from New Zealand by Hutton (1872), who 
refers to a form in the Dominion Museum, Wellington, which differs 
from P. pulchellus in having the apical plates of the arm “ very little 
swollen.” He called it “ var. B.” Farquhar (1895, p. 200) refers to 
the same specimen, and gives a description of another one obtained 
by a fisherman at the Bluff. In 1897 he suggested (p. 195) the pos- 
sibility that this “var. B.” is the “ Astrogoniwm abnormale” de- 
scribed and figured by Gray [20, pl. viii, figs. J, 2], the locality of 
which was unknown. Farquhar [16], in his List of New Zealand 
Echinoderms, definitely identifies it with Gray’s species. 
ai Lhe species presents a good deal of variation, which affects (a) the 
number of supramarginal plates, (b) the character of the abactinal 
plates, which are sometimes quite flat, at other times distinctly convex 
and even mammilliform, especially along the median line of the rays ; 
(c) but the most interesting variation is that which is presented by 
the supramarginal plates at the apex of the arm, for in some instances 
these are sufficiently enlarged as to approach the condition which 
characterizes P. pulchellus, and which alone distinguishes that species 
from P. abnormalis. 
From an examination of a series of about twenty individuals, I 
am inclined to think that the rarer P. pulchellus is merely a very ab- 
normal variation of the common P. abnormalis, but for the present 
I leave this open, for there is a distinct gap in my series between the 
most swollen plates of P. abnormalis and those of P. pulchellus. 
Mediaster sladeni, sp. nov. 
Plate VII, figs. 1-5. 
Station 29. 
A single specimen, dried; pale buff-brown. The general outline 
is not unlike that of A. miliaris. 
Measurements: R. 75, r. 35. r:R = 1: 2:14. 
The upper surface is formed of round-topped subcircular plates 
bearing numerous rounded tubercles, the plates being separated by 
papular areas. The large disc plates support a marginal series or 
circle of sixteen to eighteen more or less prismatic tubercles of unequal 
thickness, surrounding a circle of eight or ten similar but smaller 
ones, and, centrally, one, two, or three others, according to whether 
the plate itself is circular or oval in shape. 
These plates are continued on to the rays, where they are rather 
smaller than on the disc; and as the tip is approached the tubercles 
become shorter, and the tabule more convex, so as to appear almost 
hemispherical. 
