66o 



embryology: chick 



on the second day the dorsal aort^ fuse midway (Fig 515 A) 

 and thereafter the junction extends backwards, bringing together 

 the vitelhne arteries, which unite. Though there are no gills 

 aortic arches grow from the front of the heart to join the dorsal 



^^?^^ i.car. 



■a. a 



-vit.a. 



tLc.J|-^d.vJ--p-c 



r.vit.v.- \Yit.y. 

 6 



v.carr 



1. car. 



— -d.ao. 



vit. 31. 



-a\ a. 



r.vitv. 



^^^; 515-— Plans of vascular systems of chick embryos. The vessels are shown .<= 

 b"hVhTay.^ "'" ^'°^^ ^^^^^^ ^'^ indicated in outlmeTal?dLfp°p:rred^ 



"' XI A^vtr sySe^^it^h'e^fiitf ^^^^^^^^ ^'''^"^ ^'^ '^^ ^^^^^ ^^^ ^ ^. -terial system on the fifth 



AC posterior cardinal' vein ^oS porta? system'^'.fT^rrhVvifinr ' ^•'''•''•' ^'" ^^^^"'^^ ^^^ ' 

 ..can. ventral (external) caroti;! a^fries ; JtZl^^^lS^irSi^f^:'^ 



