608 CHARLES LincoLn EDWARDS, 
usually simple while in the male it is subdivided, as in Cucumaria 
frondosa. 
Spicules. — The characteristic perforated plate of the body- 
wall is somewhat elongated, smooth or knobbed, and pointed at one 
end (Fig. 22), or sometimes at both ends. Rounded and irregular 
plates are also often found but the presence of spines, or knobs 
(Fig. 23), is infrequent. The mean length is 162,9 «, with a range 
from 90—270 u, the mean diameter 88,6 «, with a range from 
63—135 « and the mean number of holes 14,4, with a range from 
2—35. There are heaps of spicules in the cloacal wall similar to 
those found in Cucumaria frondosa. Around the anus, as BRITTEN, 
1906, relates there are 5 forked teeth, or processes, which however 
I find with diffieulty in the contracted specimens. When treated 
with potash these teeth are shown as composed of closely matted, 
branched and interwoven calcareous rods. The supporting plates 
of the pedicels (Fig. 24), are more delicate. In accord with Lupwıe, 
1874, I find rudimentary end-plates and not that they are lacking 
as Britten, 1906, states. In the tentacles the supporting rods 
(Fig. 25), are straight or curved, often with larger holes. 
Polian vesicle. — In 36 of the 39 specimens examined there 
are at least 2 Polian vesicles, one arising from the ring-canal in 
the left dorsal, and the other, in the right dorsal, interradius. In 
30 specimens (77°/,), there are only 2 vesicles, and in only 2 of 
these is there a variation from the above modal condition in that 
while 1 vesicle is as usual in the left dorsal interradius, the second 
is in the left ventral interradius. There are 3 specimens having 3 
Polian vesicles, the extra vesicle being in the left ventral inter- 
radius in 2, and in the right ventral interradius in the third. Six 
specimens have 4 Polian vesicles, 5 with 2 extra vesicles in the 
left and right ventral interradii, and 1 with 1 extra vesicle in the 
richt ventral interradius and 1 from the mid-ventral radial canal. 
One specimen has 5 Polian vesieles with 1 extra vesicle in each of 
the left and right ventral and the mid-dorsal interradii. 
Stone-canal. — The stone-canal is single, having a mean 
length of 3,1 cm, with a range from 1—6 cm. In each of 2 spe- 
cimens there are 2 accessory stone-canals.. The madreporite is 
variable in form, in most cases being irregular but some are 
elongated and others pear-shaped, or lens-shaped, or irregularly 
spherical. Only 40°, have the spherical form characteristic of Cueu- 
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