152 
sunk median area in both ambulacra and interambulacra. Ambul- 
acra ca. Vi the width of the interambulacra. 7—8 ambulacral 
plates corresponding to one interambulacral plate at the ambnus. 
Pores oblique, separated by an elevated wall. Apical system half 
the h. d., peristome somewhat smaller. Oculars mainly exsert. 
Plates of the peristome few, the interambulacral ones not reaching 
the mouth edge. Radioles long and siender, ca. 1 Vs h. d. of test. 
Larger secondary spines flattened, the ambulacral ones nearly cy- 
lindrical. Large globiferous pedicellariæ (?) with elongate, flattened 
valves, without an endtooth; the small globiferous pedicellariæ 
with a distinet endtooth. Tridentate pedicellariæ (apparently) wanting. 
3. Cidavis sp , juv. 
One more species of Cidarids occurs in the New Zealand seas. 
in a dredging 10 miles N. W. of Cape Maria v. Diemen, 50 fms. 
(B/i 1915 ) I found a single specimen of a very young 
Cidarid which is easily seen to be entirely different 
from the two other New Zealand Cidarids. 
The said specimen is 3 mm in diameter. There are 
5-6 plates in the interambulacral series. No naked, 
sunk median line. The radioles (Fig. 5) are short, the 
upper ones only 2 mm long. They are very sharply and 
coarsely thorny along the edges; also on the aboral 
side there may be a distinet series of similar thorns, 
while the adoral side is nearly smooth. Secondary spines 
very few and small. Some few small globiferous pedi¬ 
cellariæ are found on the peristome. They have no 
endtooth (PI. VIII, Fig. 3). The colour of test and radi¬ 
oles is white; the apical system is faint greenish. 
It is quite impossible to identify this young Cidarid with cert- 
ainty, since its specific characters are not yet fully developed. The 
character of the radioles would seem to indicate that it is a new 
species (— of course, the radioles described above are fully formed 
ones, as is evident from the existence on them of the ostraeum- 
l ayer _). It is no use trying to trace out its relations, which could, 
at present, be nothing but guess-work; we must wait for more 
material. But the characters noted above will suffice for recog- 
nizing the species, when more material comes to hånd. The rather 
L.— 
Fig. 5. Radi¬ 
ole of Cidct- 
ris sp. 20 /i. 
