BLOOD-VASCULAR SYSTEM OF THE LORICATI TS 
specimens where there was no anterior gall-bladder artery, as 
is shown in fig. 33, there is a postertor gall-bladder artery 
(fig. 33; P.G.BI.A.) arising from the intestinal artery,,,, which 
in addition to supplying the gall-bladder is continued caudad to 
supply a portion ofthe ileum. The sPlenzc artery (Pl. IV, fig. 
31; Spl.A.) penetrates the spleen with the splenic vein, but 
before entering it, gives off a posterior gastric artery (P\. IV, 
fig. 31; P.Gas.A.), which passes beneath the spleen to the 
ventro-posterior end of the stomach; and like the posterior 
gastric artery of Ofhzodon, which, however, has a different 
origin, coming from the right pyloric ceca artery, it sends off 
a branch to the posterior portion of the intestine. 
4. Dorsal Aorta. 
This vessel (Pl. I, figs. 1, 5, and ro D.Ao.), which is the 
largest artery in a fish, arises as the most dorsal trunk from 
the common chamber (Pl. I, fig. 5; C.C.) and continues 
caudad in a median line directly below the vertebral column 
to the last caudal vertebra. At first the dorsal aorta runs 
between the 2 anterior lobes of the kidney, above and be- 
tween the dorsal branchial retractor muscles, and when the 
posterior unpaired part of the kidney is reached, runs along in 
its dorsal groove. After leaving the kidney and the body 
cavity, the aorta is known as the caudal artery (Pl. I, figs. 1, 
7,8,9 and 10; Cau.A.). It penetrates the hemal canal of the 
first caudal vertebra with the caudal vein and continues in the 
hzmal canal above the vein until the last caudal vertebra is 
reached, where at about the middle of the last centrum it 
separates into a right and a left caudal artery. The /e/t cau- 
dal ariery, (El) Mito. 18 5, Cav.A..) is) much the ‘shorten; 
it sends a branch upward in front of the urostyle, which sup- 
plies both profundus and superficial muscles. The much 
larger right caudal artery (Pl. I, figs. 1 and 8; R.Cau.A.) 
following along the outer margin of the last centrum and after 
giving off a branch in front of the urostyle similar to the left 
caudal artery, continues caudad in a median line between the 2 
hypural bones, parallel with the longitudinal hemal lymphatic 
vessel, giving off branches from both sides to the profundus 
