BLOOD-VASCULAR SYSTEM OF THE LORICATI Sil 
also sends off several branches to the other abductor and ad- 
ductor muscles, and shortly before the pelvic bones become 
united posteriorly, the ventral artery makes a short dorsal bend 
and bifurcates at right angles, one branch going to the basal 
canal of the right ventral fin rays and the other to the left. 
Each terminal branch of the ventral artery exhausts itself by 
giving off a branch to the core of each ray; proximally this 
vessel runs in the center of the cavity, but soon divides, one 
branch continuing caudad along the right side of the cavity, 
the other the left. Usually from the left branch of the ventral 
artery, but often from the right, a median vessel is given off 
caudad, which passes along the ventro-median line between the 
2 great lateral muscles and exhausts itself in numerous inter- 
costal arteries. 
This series of complicated vessels arising from the ventral 
ends of the efferent branchial arteries and anastomosing with a 
trunk of the subclavian artery may be comparable to the ves- 
sels described by Miller (pp. 36 and 37) as epigastrische Arte- 
rien, and the ventral artery or ramus epigastricus decendens of 
Miller may be analogous to the mammaria interna of mammals. 
3. Carotid Arteries. 
The short common carotid arteries (Pl. I, figs. 1 and 5; 
C.Car.A.) arise from the dorsal-cephalic corner of the first 
efferent branchial arteries, and passing cephalad a short dis- 
tance, about I cm., divide into the large external and internal 
trunks. 
(2). External Carotid or Carotts Posterior Artery (Pls. I 
and II, figs. 1, 5 and 15; E.Car.A.). — This vessel at once 
makes a dorsal-cephalic curve, passing through a foramen 
formed by a lateral process of the prootic, in company with, but 
directly below the jugular vein. Leaving this canal with the 
infraorbitalis or truncus buccalis-maxillo mandibularis and 
just ventrad and caudad of the external jugular vein, the exter- 
nal carotid passes over the dorsal edge of the hyomandibular, 
along the posterior border of the orbit, and then runs ventro- 
caudad beneath the levator muscle of the palatine arch and the 
adductor mandibulz muscles. It passes along the inner side of 
