CLASS OF BATKACHIANS. 



369 



communication is established between the arteries which 

 carry the blood to the gills and those which receive it from 

 those organs, so that the blood is no longer obliged to 



Fig. 378. Skeleton of the Frog. 



traverse the gills in order to reach the dorsal artery, and 

 thence to be distributed to the various parts of the body. 

 The artery (a) which springs from the ventricle, and which 



Fig. 379. Rainette ; Tree Frog. 



may at this time be called a branchial artery, becomes then 

 the origin of the dorsal vessel, and constitutes with it a true 

 aorta, certain branches of which proceeding to the lungs, thus 



3), which in the preceding tadpole were merely capillary, are now large, 

 and that it is with them rather than with the branchial vessels that the 

 arteries coming from the heart seem to be continued. The pulmonary 

 arteries are also much developed. Fig. 377. The same parts in the perfect 

 animal, indicated by the same letters ; the vessels which in the tadpole went 

 to the two branchiae of the second pair, are continued now with the aorta by 

 the intermedium of the anastomotic branches (2), and thus constitute the 

 two aortic arches. 



B B 



