MINUTE ANATOMY OF THE ARTERIES. 



273 



adventitia of the crural artery contains a few short longi- 

 tudinal fasciculi. According to Remak,* both in man and 

 various mammals (ox, sheep, pig), small bundles of longitudinal 

 muscles, apparent even to the naked eye as whitish masses, are 

 recognisable on the external surface of the arch and thoracic 

 portion of the aorta.f In oxen, sheep, and pigs, Remak was 

 able to follow the longitudinal muscles as far as the iliac 

 arteries, and in the sheep he found them in the pulmonary 

 artery and its branches. In the arteries distributed to the 



Fig. 48. Longitudinal section through the coat of the thoracic 

 aorta, a, elastic plates ; b, transverse muscles in section ; c, longitu- 

 dinal muscles. 



viscera, Remak found external longitudinal muscles only in 

 the trunk and in the primary divisions of the superior mesen- 



* Miiller's Archiv, p. 96, 1850. 



I can corroborate this statement in the case of the calf. 



