Hieroglyphics of Horapollo, tr. Alexander Turner Cory, , at sacred-texts.com
To denote a watchful person, or even a guard, they pourtray the HEAD OF A LION, because the lion, when awake, closes his eyes, but when asleep keeps them open, which is a sign of watching. Wherefore at the gates of the temples they have symbolically appropriated lions as guardians.
I. III. Andro-Sphinxes, and Crio-Sphinxes, were almost universally placed in the dromos of a temple. The magnificent lions, presented by Lord Prudhoe to the British Museum, are from Napata, now Gebel Burkel.