i40 



THE COMMON FROG. 



[chap. 



/ ./^Sf- •• 





Fig. 85. 



Fig. 86. 



c— -\ 



k 



Fig. 87. 



Fig. 88. 



Fig. 85. — Diagram representing; the primitive aort'c arches of Mamma's and Saii- 

 ropsidans (after H. Rathkf-). n, common trunk, or root, of the aorta ; /', b, the 

 two branches into which it divid- s, and which give off the successive arches i, 2. 

 3, 4, and 5, which end in c, c, two vessels which again unite to form d, the de- 

 scending, or dorsal, aorta. 



Fig. 86. — Diagram representing the vessels and aortic arches of a Lizard, with the 

 changes induced on the primitive condition (after H. Rathke). a, a, internal 

 carotids : b, b, external carotids ; c, c, c jmmon carotids ; d, d, anastomosis be- 

 tween the interna! carotids and the secondary aortic arches : e, e. right mam 

 aortic arch ; /, /, the subclavian arteries (which give oft' the vertebral, here not 

 represented) ; g. commencement of the great dorsal aorta ; /', h, left main aortic 

 arch ; ?', /, i, p'dni.inary arteries ; k, k, rudiments of the first (right and left) 

 aortic arches— Nos. 5, 5, of Fig. 85. 



Fig. 87. — Diagram representing the main arteries of a Bird (fowl) with the changes 

 induced nn the primitive condition (after H. Rathke). a, a, int rnal carotids ; 

 b, b, external carotids ; c. c, common carotids ; d, root of main aorfc arch (here 

 right) ; t', arch of the same \ f, right subclavian fwhijh arive-, from the anistomosis 

 ot the first two right primitive aoitic arches) -.g, commencem^'nt of the descending 

 aorta ; h, h, 'eft Mibclavian ; z, i, t\ pulmonary aneries ; /c. righ', and /, left, 

 rudiments ot the primitive aort'c arches. 



Fig 88. — Diagram representing the main arteri s of a Mammal with the changes 

 inHuced in the primitive condition 'after H. Hathk-). n. b, c, carotids, as before ; 

 d, root of main aortic arch (here 1-fc); e, arch of the same ;/, coin men cement 

 of descending aorta; g, left vertebral artery ; /i, left siibcli>ian ; z, right sub- 

 clavian; k. right vertebral arrerv ; /. cominuatioii of right subclavian; m, piil- 

 muiijry artery ; «, remnant of left primitive aortic arch. 



