TYPE CRUSTACEA. 



389 



FlG. 175. Daphnia pulex (from HERTWIG). 



& = brood-pouch. 

 e = immature ova. 

 g = cerebral ganglion. 

 go optic ganglion. 

 h = heart. 

 )c = germinal region of ovary. 



= ovary. 



s = shell gland. 



1 = antennule. 



2 = antenna. 



3 = mandible. 



5-9 = thoracic limbs. 



