BLOOD-VASCULAR SYSTEM OF THE LORICATI 83 
The ophthalmic vern proper (Pls. I, II and III, figs. 1, 5, 13, 
15 and 19; Oph.V.) arises as a sinus-like vessel from the dor- 
sal region of the anterior horn of the choroid sinus, but grad- 
ually tapers down into its caudal course, and when immediately 
ventrad of the optic nerve receives a much smaller branch from 
the posterior horn. Curving around to the posterior side of the 
optic nerve it penetrates the silver layer of the choroid and the 
sclerotic coat. Once outside of the eyeball the ophthalmic vein 
pursues an oblique dorsal course, and, passing between the su- 
perior and external recti muscles it unites with the rectus and iris 
veins to form the internal jugular. 
Iris or Ophthalmic Minor Veins (Pl. II and III, figs. 13, 
15 and 19; Ir.V.).—A single iris vein arises from the capillar- 
ies in the dorsal part of the iris. Together with the ramus cil- 
iaris longus and the iris artery it passes ventrad a short distance, 
between the silvery and vascular layers of the choroid (see fig. 
1g), and then penetrates the silvery layer and the sclerotic coat. 
After running along the posterior dorsal surface of the eyeball 
it passes between the superior and external recti muscles, but 
laterad to the ophthalmic vein. In its caudal course it receives 
a branch from the external rectus muscle, and finally terminates 
by uniting with the rectus and ophthalmic veins to form the 
internal jugular. 
Optic or Feetina Vein (Pl. Ill, figs. 19 and 20; Opt.V.). — 
In the specimen from which figs. 19 and 20 were drawn I 
noticed a small vein penetrating the sclerotic coat just ventrad 
of the optic artery. Its connection with the larger vessels had 
been destroyed before the vein was noticed, and internally the 
vein was not injected. Several specimens were injected espe- 
cially to demonstrate this vessel, but in every case this vein 
failed to become injected. It is probable, however, that this 
vein follows the course of the optic artery, returning the venous 
blood from the lens, falciform process, and the retina, and very 
likely empties into the ophthalmic vein. 
As has already been stated in the first paragraph under (4) 
the internal jugulars are connected with one another by a sinus- 
like vessel, which crosses the eye-muscle canal. Leaving the 
eye-muscle canal with the ciliary nerve and the iris artery, 
