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 off is a hyoid (hy, 
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-fig, 37. 
Aortic arches and first part of dorsal aorta of Gerrhosawrus flavigularis. 
Ca. Carotid; g. Gastric; I.c. Vertebral artery; hy. Hyoid artery ; 1. Muscular 
twig; os. @sophageal branches; P. Pulmonary arch; Se/. Subclavian. 
main trunk of the carotid arises. The trunks are here so twisted 
that the carotid stem is given off 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 
