BLOOD-VASCULAR SYSTEM OF THE LORICATI Wl 
along the ventral surface of the left optic nerve, and shortly 
before the olfactory lobes are reached they bear off laterad 
around the optic nerves, but, before leaving them, each vessel 
gives off a branch, which continues along the ventral surface 
of the nerve to the eye. This is the oftcc or retina artery (Pl. 
Ill, figs. 22, 23, and 25; Opt.A.), which gives off branches to 
the nerve and finally penetrates the eye-ball a little cephalad of 
the nerve. Once inside the retina it continues along the retina 
fissure (see fig. 22), giving off branches to either side and 
especially to a whitish gland-like body situated on the side of 
the fissure close to the falciform process. The main portion of 
the artery, however, breaks up on the falciform process, the 
campanula Halleri, and even extends over on the lens. It is 
also probable that the retina receives nourishment from the 
choroid arteries, which are separated from the retina only by 
the thin pigment layer of the choroid. The main anterior cere- 
bral artery after curving around the optic nerve divides into an 
anterior and a posterior portion. Close to the point of bifurca- 
tion the anterior branch sends forward a small vessel, which 
runs along the ventral surface of the olfactory nerve, but the 
main trunk passes inward and anastomoses with its fellow in 
the median line. This point of union marks the source of 2 
vessels, a smaller dorsal one designated as the most anterior 
cranial cavity artery (Pi. Ill, fig. 23; C.C.A.), coming up 
between the olfactory lobes to supply the adipose tissue in the 
anterior region of the cranial cavity and a larger caudal vessel, 
which runs in a median line between the optic nerves and the 
cerebral hemispheres, giving off several branches to the latter 
through the median fissure. The posterior branch of the 
anterior cerebral artery is a superficial vessel; it follows caudad 
along the ventro-lateral surface of the cerebrum, passing between 
it and the optic nerves, and giving off superficial branches to 
the ventral surface of the cerebrum and the anterior surface of 
the mesencephal. Sometimes the right, but more often the left 
artery continues dorsad with the epiphysis as the second cranzal 
cacy artery (laine) 2301. BANS): 
The posterior cerebral arterzes (P\. III, figs. 23 and 25; P.- 
Cer.A.) come off from the encephalic artery at right angles to 
