52 ALLEN 
the metapterygoid, and after receiving the hyoidean artery 
comes to the outer surface through a foramen between the sym- 
plectic, hyomandibular, preopercular, and quadrate bones. 
This combined vessel, which may be designated as the mandzb- 
ular artery (Pl. 1, fig. 1; Man.A), makes a sharp cephalic 
bend, passing over the outer surface of the quadrate bone and 
then curving inward around it to the inner surface of the man- 
dible, where it terminates in 2 branches, which supply the ad- 
ductor mandibule muscles. The main branch runs along the 
inner dorsal surface of the bone, while the smaller branch sup- 
plies the ventral portion of the muscles. 
Along its ventro-cephalic course the external carotid sends 
off many branches in the facial region and receives one. The 
first vessel to be given off is the sclerotic-cr7s artery (P1. II, 
fig. 15; Scl.Ir.A.). This rather small vessel arises from the 
dorsal surface of the carotid immediately after it leaves the 
canal formed by the prootic process. Close to its source the 
sclerotic-iris artery gives off caudad the most anterzor cranial 
cavity artery (Pl. II and III, figs. 15 and 24; C.C.A.), which 
penetrates the skull through the middle and the largest of the 
prootic foramina, along the dorsal surface of the roots of the 
V nerve, and follows up the anterior surface of facialis portion 
of the ramus lateralis accessorius to supply the adipose tissue 
in the anterior portion of the cranial cavity. The main trunk, 
however, continues cephalad ‘a short distance along the outer 
surface of the prootic dorsad of the gasserian ganglion, and 
here divides, one branch, the sclerotic artery (Pl. II, fig. 15; 
Scl.A.) continues cephalad, but laterad to the truncus supra- 
orbitalis or ramus ophthalmicus and the orbito-nasal vein. 
When the orbit is reached, instead of curving inward around 
the eye with the nerve and vein, it continues in a straight line 
over the dorsal surface of the eyeball in company with the 
sclerotic branch of the truncus supra-orbitalis and the sclerotic 
vein, to supply the adipose tissue surrounding the dorsal surface 
of the sclerotic coat. The other branch is the zv7s artery (Pls. 
II and III, figs. 13, 15 and 19; Ir.A.), which enters the skull 
through a foramen bounded by the dorsal process of the para- 
sphenoid, the alisphenoid, and the prootic. Together with the 
