LYNCEIDiE. 
119 
The use of these organs is the same as in the Daphniadae, 
being chiefly organs of locomotion. 
The brain is apparently the same in situation and in 
shape as in the Daphniadae. The mouth also is nearly of 
the same construction. 
The mandible (t. XV, f. 1 c) is a strong organ, articula- 
ting superiorly with the body by a sharp and pointed 
extremity, whilst the inferior extremity is free and unat- 
tached, curved a little inwards, and rounded somewhat at 
the tip, which is furnished with several strong teeth. 
The labrum (t XV, f. 1 d) consists of a large, strong 
plate, articulating wiih the body by the narrow end, to 
which are attached the muscles which move it. About the 
centre of its length it takes a sudden curve, and descends 
in the form of a broad plate, which is slightly lunated at 
the extremity, the edges terminating in sharp points. 
To the lower edge of its superior extremity is attached a 
flat, rather square plate, which moves simultaneously with 
the other part, and to which it seems firmly fixed. These 
organs may be seen almost constantly in motion when the 
animal is stationary, the motion of the mandibles being 
pretty quick and oscillatory, whilst that of the labrum is 
slow, upwards and downwards. 
The jaws consist of a flat body, armed at the extremity 
with several stout spines (t. XV, f. 1 d*). 
Part of the digestive canal may be seen also in the upper 
part of the animal, commencing, as in the Daphniadae, 
immediately behind the mouth, in the form of an 
oesophagus, and terminating in the stomach, which is 
situate in the lower portion of the shell. 
The stomach (t. XVI, f. 1 b) differs somewhat from that 
organ as seen in the Daphniadae, being curved or twisted 
into one or two complete convolutions near the centre. 
The body of the animal is not jointed, as in the Daph- 
niadae, and is quite free and unattached within the valves 
of the shell, except at the superior portion, where we see 
it attached to the posterior edge of the shell by about 
three rather broad muscles. It terminates superiorly in 
