On some West-Australian Entomostraca. DT 
ing such a pronounced gibbous prominence as in the last- 
named species. Whereas the left valve has the edge quite 
smooth throughout, the right one, as in all other species 
belonging to this genus, has, inside the anterior and posterior 
extremities, a series of small tubercles, giving this part of 
the edge a minutely crenulated appearance. 
The surface of the shell is perfectly smooth and 
polished, with only the usual small scattered pits, and is 
hairy only at each extremity. In the centre of each valve 
the impressions of the adductor muscle of the shell are easily 
observable, exhibiting the usual number and arrangement. 
The colour of the shell is light yellowish, sometimes 
with a slight olivaceous tinge, and clouded dorsally, behind 
the eye, with dark sepia. The cecal appendages of the 
intestine shine through the shell with a dark green colour, 
and just above them the shell generally exhibits a reddish 
orange tinge caused by the ripe ova accumulated within 
the body. 
The eye is seen fairly well through the shell; it is of 
moderate size and normal structure. 
The several appendages of the body almost exactly 
agree in their structure with those in C. dentato-marginatus, 
as described in detail by the present author in his above- 
quoted paper. 
The caudal rami (fig. 4) are of moderate length and 
quite straight, tapering slightly distally. They are armed 
in the usual manner, each having at the tip 2 unequal, 
slender claws, the outer of which is the longer, and some- 
what exceeds half the length of the ramus. Just in front 
of it, there is a rather small bristle, and at a short distance 
from the proximal claw, the somewhat longer dorsal bristle 
is seen to originate, 
