Differentiation. 283 



phin. The commonest variation of the aortic arch is where the innomi- 

 nate gives off the left carotid as well as the right, and so supplies both 



Fro. 114. Four specimens of Human Anom- 

 alous formations of the aortic arch and its 

 branches. 



re, lc. Right and Left carotid arteries, go- 

 ing to the head. 



r.s, Is. Right and left subclavian arteries, 

 going to the arms. 



i. Innominate artery. 



sides of the head ( See Fig. 114 A), 

 the artery supplying the left arm 

 coming off as usual. This is the nor- 

 mal condition in Apes, Bears, Dogs, 

 and all the feline tribes ( Lion, Tiger, 

 Cat, Leopard, &c. See fig. 115 D). 

 In some rare cases in man one branch 

 only comes off from the aortic arch, 

 and this again divides into the various 

 arteries supplying the head and arms. 

 In Horses and other solipeds, we see 

 this form of aortic arch. (See fig. 114 D and 115 A.) Again, the 

 branches may all be given off separately from the arch, as is the arrange- 



C \/? c ^o 



FIG. 114. 



FIG. 115. 

 FIG. 115. Origin of Arteries from Aortic Arch in some Mammals. ( Owen.) 



B. Lama. 

 E. Otter. 

 H. Man. 



C. Giraffe. 

 F. Gibbon. 

 I. Dugong. 



[references same in all. 



' of Veterinarians or " innominata " of human anatomy, 

 c. Right Carotid artery. c' the left. 



d. Brachial artery ( to the right arm ). d' " 



v. ' Vertebral artery, or right Thoracic. v 1 " 



ment in the Walrus." (See Fig. 114 C. } "I have three times met 



A. Ox. 

 D. Lion. 

 G. Hedgehog, 

 a. Main Aorta. 

 6." Anterior Aorta 



