1905.] 



OF THE YELLOW-THROATED LIZARD. 



263 



some other Lizards, though they agree, as might be expected, in 

 their main features. The first branch given ofi" is a hyoid (Jiy, 

 text-fig. 37), which supplies the hyoid region generally; I have 

 not followed its branches minutely. In this region the carotid 

 is in close contact with the systemic arch. Further dorsally they 

 part company, and, shortly after this separation has occurred, the 



Text-fis-. 37. 



Aortic arclies and first part of dorsal aorta of GerrJiosaurusflaviffularis. 



Ca. Carotid; ff. Gastric; I.e. Vertebral artery; %. Hj'oid artery; 31. Muscular 

 twig ; ces. CEsopliageal branches ; P. Pulmonary arch ; Scl. Subclavian. 



main trunk of the carotid arises. The trunks are here so twisted 

 that the carotid stem is given ofi" posteriorly and dives under 

 the carotid arch to reappear on its anterior face. The rest of 

 the carotid arch is to be regarded as ductus Botalli. From this 

 section arise two arteries : the first is a small muscular twig ; the 



