CRAYFISH 



257 



Anfennule 



Antenna 



Chelipods 



Opening of 

 green gland 



Third 

 maxilliped 



p&rejopods 



Pleopods 



Profopodite 

 Exopodife 



swjmmerefs 

 Swtmmerefs 



C/ropocf 



-Endopodife 

 Telson Anus 



Fig. 162. — Under side of Cambarus virilis Hagen, a common species in the central states. 

 From a male specimen from Wisconsin. X %. 



Musc/es 



Heart 

 Pericardium 

 Vas deferens 



Sterna f artery 



Oill 

 chamber 



6ill 



Ventre/ / I ^„f ^^J^ 

 thoracic artery \ °'^ '^3 



Ventral nerve 

 cord 



Fig. 163. — Diagrammatic cross section through a crayfish (Cambarus) in the posterior part 

 of the cephalothorax, to show the gill chambers and gills. 



