50 COMPARATIVE ANATOMY 



artery, passing to the stomach and intestines. The systemic 

 arches give off on either side before they unite to form the 

 dorsal aorta (i) a laryngeal artery, a small vessel arising 

 from the proximal part of the arch, and passing forwards to 

 supply the larynx; (2) an oesophageal artery, arising from the 

 dorsal side of the upper part of the arch, and turning down- 

 wards to supply the oesophagus ; (3) an occipito-vertebral 

 artery, arising from the dorsal side of the arch opposite the 

 transverse process of the second vertebra, and dividing after 

 a short course into two branches (a) the occipital artery, 

 which courses forward, supplying the sides of the head and the 

 jaws, (&) the vertebral artery, running backwards parallel to the 

 vertebral column, and dorsal to its transverse processes : it gives 



Fig. 8. 



The Frog dissected from the right side to show the distribution of the chief 

 arteries ; semi-diagrammatic. H, heart ; tr, truncus arteriosus ; caf, carotid 

 arch ; /, lingual artery ; ca, carotid artery ; sy, systemic arch ; <a, oesophageal 

 artery ; oc.v, occipito-vertebral artery ; sc, subclavian artery, cut short ; ao, 

 dorsal aorta ; ccel, cceliaco-mesenteric artery, supplying the viscera ; its 

 three main branches are indicated but all its subdivisions cannot be shown ; 

 ra, uro-genital arteries ; //, iliac arteries ; PC, pulmo-cutaneous arch, divid- 

 ing into /, the pulmonary artery supplying the lung, and cu, the cutaneous 

 artery, cut short ; La, larynx ; L, lung ; S, stomach ; /, intestine ; R, 

 rectum ; Bl, bladder ; M, muscular abdominal wall turned back ; K, kidney. 



off branches to the muscles of the body and to the spinal cord ; 

 (4) a subclavian artery, arising from the arch close behind 

 the occipito-vertebral, and supplying the shoulder and fore- 

 limb. 



