t/ aq 



Fig. 76. — A diagrammatic figure showing the arrangement 



OF THE BLOOD VESSELS IN A CHICK EMBRYO AT THE END OF THE 

 FIFTH DAY OF INCUBATION. ThE AMNION HAS BEEN REMOVED, AND 

 THE VITELLINE VESSELS CUT SHORT A LITTLE DISTANCE FROM THE 



EMBRYO. (After Marshall.) 



A, dorsal aorta. A^, A*^ A^^ third, fourth, and fifth aortic arches of the 

 right side, lying in the first, second, and third branchial arches respectively. AA^ 

 allantoic artery. ^^, basilar artery. AC^ carotid artery. AH, caudal artery, 

 the terminal portion of the dorsal aorta. AL, lingual artery. AP, pulmonary 

 artery. A V, vitelline artery. EI^ auditory vesicle, RA , right auricle, RS, 

 sinus venosus. RT, truncus arteriosus. RV, right ventricle. 7W, allantois. 

 VA, allantoic vein. VB, anterior cardinal vein. VC^ posterior cardinal vein, 

 VD, Cuvierian vein, KA", meatus venosus. VH^ efferent hepatic vessel. VI, 

 posterior vena cava. VJ, jugular vein. K(9^ afferent hepatic vessel. FK, vitel- 

 line vein. 



247 



