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 ffisophageal 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, (ft) the vertebral artery, running backwards parallel to the 

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



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

 arteries ; semi-diagrammatic. H, heart ; tr, truncus arteriosus ; ca! ', 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, coeliaco-mesenleric 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 ; A", 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. 



