352 



ARTICULATA : CRUSTACEA. 

 FIG. 478. 



- Mandibles. 



First pair of jaws. 



. Second pair of jaws. 



Auxiliary jaws or foot-mandibles. 



,- Auxiliary jaws or foot-mandibles. 



Auxiliary jaws or foot-mandibles. 



The six pairs of locomotive appendages of a Crustacean Craw-fish which are modi- 

 fied so as to constitute the masticatory apparatus. 



FIG. 479. 

 saa sa bv h ha oa aa 



vs vs br 



Circulatory and Respiratory apparatus of a Crustacean Craw-fish. 

 aa, antennar artery ; oa, ophthalmic artery ; ha, hepatic artery ; h, heart ; bv, 

 branchio-cardiac vessels carrying blood from the brauchiiB to the heart ; sa, sternal 

 artery ; saa, superior abdominal artery; us, vs, veuotis sinuses receiving blood from 

 the various parts of the body, and transmitting it to the brancliiiE or respiratory 

 apparatus br. 



