MYODOME AND TRIGEMINO-FACIALIS CHAMBER 287 
The foramina for the internal carotid arteries are cut in the sec- 
tion, lying in the floor of this space and separated from each other 
by a median piece of cartilage which lies at a slightly lower level 
than the cartilage on either side of it. The internal carotid 
arteries are shown lying ventral to the basis cranii, each artery 
accompanied by, and lying mesial to, the nervus palatinus faci- 
alis of its side. No parasphenoid bone is shown, but compari- 
son with a figure of a 47-mm. embryo (Gaupp, 705 b, p. 763) 
shows that that bone lies ventral to the nerve and artery and 
forms the floor of the canalis parabasalis of Gaupp’s later de- 
scriptions (’05 a, p. 292), this canal of Lacerta thus being the ho- 
mologue of the palatine canal of my descriptions of Amia. The 
piece of cartilage between the foramina carotica is the intertra- 
becula of Fuchs’s (712) descriptions of Chelone, and, as it forms 
part of the floor of the little space here under consideration, it 
cannot be part of the crista sellaris, as the lettering in Gaupp’s 
figure of the entire chondrocranium of Lacerta (’00, fig. 1) 
would lead one to suppose. The nervus abducens enters the 
space here under consideration by traversing a foramen which 
perforates the cartilage of the chondrocranium, lateral to the 
lateral end of the crista sellaris, and issues from it into the orbit. 
No pituitary veins are shown in Gaupp’s figure of a cross-sec- 
tion through this region in Lacerta, but in an earlier work (’93, 
p. 571) he fully describes them. A vein lies along each lateral 
surface of the middle lobe of the hypophysis and is connected 
with its fellow of the opposite side by several cross-commissures, 
the largest of which lies posterior to the hypophysis. From 
either end of this posterior cross-commissure an important vein 
leads into a large vein which drains the blood from the orbital 
venous sinus, and the vessel so formed falls posteriorly into the 
vena jugularis interna. These veins thus must traverse the 
space of uncertain dimensions mentioned in my earlier work, 
which is a dorsal myodomic cavity. The internal carotid ar- 
teries run upward through the fenestra hypophyseos, and then 
along the lateral surfaces of the lateral lobes of the hypophysis, 
lying, in their course, anteroventral to the pituitary veins. 
