Sheep and goat heads were collected from a slaughter house and the bif
urcation of the common carotid artery was preserved in 10% formalin so
lution. Specimens were processed according to standard histologic tech
nique and stained with different stains. Due to the absence of the int
ernal carotid artery in adult sheep and goats, different theories were
put forth by several researchers concerning the fate of the carotid b
ody and carotid sinus in these animals. However, the carotid body was
found close to the muscular branch of the occipital artery and was rep
resented by either scattered cells or masses around the vessel. The si
nus was at the base of the occipital artery in both species. Therefore
, we can conclude that carotid body and carotid sinus developed at the
se sites regardless of the presence or absence of the internal carotid
artery.