34 
BRITISH ENTOMOSTRACA. 
those of the first pair, and having two or three short hairs 
at the base of each joint. 
The organs of the mouth consist of one pair of 
mandibles and two pairs of jaws. The mandible is 
composed of a basilar portion, which is short and pro- 
vided with two large teeth curved inwards, and a long 
palpiform branch, formed of three joints, of which the 
last two are much the longest. Behind these mandibles 
we see a small inferior lip, consisting of two slender 
scales ciliated on the edges, and united by a peduncle. 
The first pair of jaws (t. II, f. 1 a) are formed of a 
stout basilar joint, which has on its internal edge a 
ciliated plate, and gives origin at one extremity to a long 
filiform stalk, which is directed first forwards, then is 
curved upwards and backwards, and is prolonged to the 
extremity of the thorax, between the internal surface of 
the carapace and the flanks. This stalk is divided into 
several articulations, each of which is furnished with long 
hairs. The second pair of jaws have a very large basilar 
joint, somewhat of a quadrilateral shape, the internal 
edge of which is divided into several lobes, and strongly 
ciliated, and the inferior edge gives attachment to two 
branches, one of which is composed of two ciliated arti- 
culations, and the other of only one. Succeeding these 
organs of the mouth, we next find eight pairs of branchial 
feet, inclosed entirely within the carapace (t. II, f. 1 d). 
They are of a foliaceous structure, are very slender, placed 
very close to each other, and are attached to the eight 
thoracic segments of the body. Each of these branchial 
feet consist of three portions : 1st, a lamellar piece, 
forming the internal branch, and occupying the whole 
length, and which, of considerable size at the base, becomes 
much narrower at its inferior half; 2d, a large mem- 
branous plate, nearly as long as the internal branch, to 
which it is attached at its upper external part ; and, 
3d, another membranous plate, placed between the two 
preceding, and attached also to the upper and external 
edge of the internal branch. 
