LYNCEID^. 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 <?) 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 labruni (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 </*). 



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) difl^ers somewhat from that 

 organ as seen in the Daphniadae, being cm^ed 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 tenninatcs superiorly in 



