84 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
artery (fac. art.), which supples the mandibles and the 
lateral regions of the face. Neither the injections nor the 
serial sections showed any oesophageal ring of the nature 
described by Delage. Several small arteries are given off 
from the posterior border of the antenno-facial arteries 
which supply the oesophagus (ces. art.) and neighbouring 
soft parts, as will be seen from the figure. The fact that 
in many cases these small arteries dilate to an exaggerated 
extent when injected, may account for the mistake. 
The lateral arteries (Pl. III., fig. 1, dat. art.) run 
forward and outward from the anterior end of the 
heart, and in the first thoracic segment each anasto- 
moses with the transverse artery from the dorsal 
aorta. On the external side of each lateral 
artery, four thoracic arteries arise (1., 11., l11., Iv.), 
supplying the first, second, third and fourth thoracic 
segments. On the internal side of the thoracic artery a 
number of branches are given off which ramify on the 
walls of the gut (nt. art.) and hepatic tubules (hep. art.). 
Close to the origin of the fourth thoracic artery a large 
branch (gen. art.) is given off, which supplies the terminal 
portion of the vas deferens. A number of arteries arise 
from the dorsal side of each lateral artery, and ramify 
in the hypodermal tissues. 
The thoracic arteries (i., il., ill., iv., v., vi., vil.).—The 
course of each of the thoracic arteries, with the exception 
of the sixth and seventh, is somewhat the same. Each 
runs directly outwards, and, when dorsal to the hepatic 
tubules, gives off a ventral branch which supphes these. 
Pollowing the curvature of the dorsal surface the artery 
curves ventrally; a small artery arises which runs into 
the dorsal longitudinal muscles. When it reaches the 
insertion of the limb it bifurecates, the inner branch runs 
inwards and supphes the ventral surface, the outer branch 
