172 



HOMOLOGY 



This pressure forces the blood out into arteries as follows: 

 one unpaired median artery, ophthalmic, which conveys blood 

 to the eyes and surrounding organs; one pair of antennary 

 arteries from the anterior sides of the heart, leading to the 



white 

 portion 



cortical 

 portion 



cortical portion 



portion 



FIG. 71. Diagram of the kidney of a crayfish (Astacus fluviatilis) . 

 Parker and Haswell after Marchal.) 



(From 



antennae and adjacent organs; one pair oi-hepatic arteries from 

 the lateral ventral part of the heart which are quickly lost in 

 branches in the hepato-pancreas ; one unpaired dorsal abdominal 

 artery from the posterior angle of the heart, and one unpaired 

 sternal artery which passes directly downward from the 

 posterior ventral portion of the heart to the ventral surface 

 where it enters the ventral artery which traverses the entire 



