MALACOSTRACA 



353 



the maxillae : large food masses are seized by the endopodites of the 

 thoracic limbs. 



My sis (Figs. 253, 257), British, possesses a statocyst on the 

 endopodite of each uropod, but has not the branched gills (thoracic 

 epipodites) which are found in some of the Mysidacea (Lophogas- 

 tridae). Its respiration takes place through the thin lining of the 



-can 



-th. 1 



Fig. 257. 

 Fig. 257. Maxilla of Mysis. bri. bristles used in straining out the food; 

 en. endopodite; ex. exopodite; 1-6, segments. 



Fig. 258. Part of a transverse section through the hinder region of the head 

 of Hemimysis. After Cannon and Manton. bri. bristles of the fringes on the 

 maxillae by which food particles are strained out ; car. the edge of the cara- 

 pace; hd. head; mx.' base of maxillule; mx." section of maxilla; th.i, section 

 of first thoracic limb; th.i, ed. section of endite of first thoracic limlb. 



The arrows show the direction of the currents. Note that the outgoing 

 water from the food current joins that of the respiratory current, which comes 

 down from under the carapace. 



carapace, under which a current is drawn from over the back by the 

 action of the epipodites of the maxillipeds (first pair of thoracic 

 limbs). 



Order CUMACEA 



Peracarida with a carapace which covers only three or four thoracic 

 somites but is on each side inflated into a branchial chamber and pro- 

 duced in front of the head to lodge the expanded end of the exopodite 

 of the first thoracic limb ; eyes (when present) sessile ; no exopodite 

 on the antenna; three pairs of maxillipeds; a large gill on the 

 I St thoracic limb and natatory exopodites on some of the others; and 

 slender uropods, which do not form a tail fan. 



BI 23 



