518 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
cephalic vessel joins the anterior vena cava, a wide vessel 
running over the ventral wall of the cranial cartilage and 
the liver, down to the kidneys. At the anterior end of 
these it bifureates, and each half runs behind the 
corresponding kidney and soon meets a vessel running in 
from the middle region of the venous sinus (fig. 52, 
Abd. V.). These two vessels join to form the Lateral 
Vena Cava of that side, which slants outwards and down- 
wards to the branchial heart, behind the kidney (fig. 52, 
L.V.C.). From the antero-external angle of this heart 
the blood is led by the afferent branchial vessel to the 
gill, and is distributed to branches which feed each 
filament, and becoming aerated as it passes through the 
thin gill laminae, is collected again into the efferent vessel 
of the gill. The circular cephalic vessel also receives the 
venous blood from the superficial muscles of the head and 
neck by means of small branches which run into its 
aboral wall (fig. 52, Ceph. V. and Sup. V.). . The ventral- 
most of the eight interbrachial vessels appears to run into 
the cephalic vein sometimes to the right and sometimes 
to the left of the origin of the anterior vena cava. Some 
superficial muscles must be dissected away to expose the 
circular vessel fully. 
Below the origin of the second ventral interbrachial 
vessel on each side, a large vessel runs in from the 
surface of the mantle and the eye (fig. 52, W@.V.). The 
origin of this vessel is in the mantle. The whole of the 
anterior part of the mantle is drained (PI. VII, fig. 57) by 
a series of vessels of which only (1) is on the internal 
surface, while (2, 3 and 4) are external. These four 
vessels unite to form one, which then receives a branch 
from the postero-dorsal surface of the eyeball, and one 
from the corresponding lateral wall of the funnel 
(fig. 52! #,V,). Running up the ventral surface of the 
