232
THE BIOLOUY OF EWHAUSIIDS
ocular sinuses through a sinus, the photophore sinus, which surrounds
the sides and inner surface of the photophore. The second branch of
the optic artery supplies the nerve ganglion, the medulla terminalis
(Fig. 81), with a system of fine vessels which spread throughout the
tissues and some of which also supply part of the medulla externa. The
main artery then curves round the nerve ganglia towards the dorsal
side of the eye and supplies the medulla externa and medulla interna.
B