LIGUA. 85 
soon bifurcates again, the dorsal branch supplying the 
epimeral (ep. art.) region, and the ventral branch is the 
crural artery supplying the leg (cr. art.). The inner 
branches of the first thoracic artery supplying the 
ventral surface of the first thoracic segment unite 
in the mid-ventral line at the base of the maxilli- 
pedes, forming a median artery (Pl. III, fig. 2) 
which runs forwards and gives off paired arteries to the 
maxillipedes (map.), second (mz) and first maxillae (ma’), 
and terminates in the lingua-like lower lp. 
The sixth thoracic artery soon after its origin gives 
off a branch which runs ventrally, and unites with its 
fellow of the opposite side in the mid-ventral line of the 
intestine; from the point of junction a median artery 
runs forwards and backwards, forming a sub-intestinal 
artery. From the sides of the sub-intestinal artery paired 
transverse branches arise in a very regular manner, and 
run on the walls of the intestine in the oblique grooves 
which have been described above. 
The seventh thoracic artery, after running obliquely 
backwards for a short distance, gives off an artery which 
bifurcates and supplies the lateral regions of the intestine. 
It soon gives off from its posterior side a large artery, the 
abdominal artery which runs posteriorly; the rest of its 
course is similar to that of the other thoracic arteries. 
The abdominal artery (PI. III., fig. 1, ab. ait.) 
of each side runs in an undulating manner, midway 
between the lateral margins and_ the median line; 
from it arise small arteries supplying the intestine, 
muscles and other tissues. In the third abdominal 
segment it gives off a ventral branch which supplies 
the three anterior branchiae and the body-wall. The 
fourth and fifth pairs of abdominal appendages are 
supplied by an artery which arises from the abdominal 
