BRANCHIOPODA 319 



of them is directed towards the mouth as a process with a blunt, 

 roughened end. Below, the head bears (a) the large lahrum which is 

 directed backwards under the mouth ; {b) the maxillules^ a pair of 



^00 p. 



Fig. 225. A female of Chirocephaliis diaphanus. The animal is seen from 

 the right-hand side in the morphological position: normally it swims up- 

 side down. ah. 1, ab. 7, first and seventh abdominal somites; al. alimentary- 

 canal ; an/ antennule ; an." antenna ; e. compound eye ; e.' median eye ; egg p. 

 egg pouch; h. heart; Ibr. labrum; Ir. liver; md. base of mandible; nk.on. neck 

 organ; ov. ovary; ram, ramus of caudal fork; tel. telson; th. 11, eleventh 

 thoracic limb; th. 12, twelfth thoracic somite. 



nk.on. 



--yan. 



pr.ep. 



Fig. 226. Fig. 227. 



Fig. 226. A front view of the head of a male Chirocephaliis. an.' antennule; 

 an." antenna; e. compound eye; e.' median eye; fr.ap. frontal appendage; 

 nk.on. neck organ. 



Fig. 227. A thoracic limb of Chirocephaliis, mounted flat. br. branchia; 

 bri. bristles which strain out the food ; ep. epipodite; ex. exopodite ;yZ6. flabel- 

 Xwcn; pr.ep. proepipodites ; 1-7, endites. 



small triangular plates fringed by long bristles; (c) the maxillae^ 

 which are microscopic vestiges, each bearing three spines. 



Behind the head come eleven thoracic somites which bear each a 

 pair of phyllopodia. Fig. 227 shows that these possess all the 



