512 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
ARTERIAL SYSTEM. 
The arterial blood in Eledone, as in Octopus, is 
wholly enclosed in definite vessels. These have muscular 
walls, which are consequently stronger and thicker than 
the membranous walls of the veins. The pressure of the 
blood in the arteries is very great indeed, but is slight in 
the veins (Frédéricq). As mentioned previously, the 
arteries of Hledone radiate from three main trunks :— 
(1) Anterior aorta, carrying blood to the cephalopedal 
mass, the mantle and anterior portion of the alimentary 
canal; (2) abdominal aorta, carrying blood to the 
intestine and ink sac; and (3) genital artery, running 
direct to the genital gland. 
The anterior aorta is a large vessel which, leaving 
the heart, runs forwards, and curving round the liver 
runs dorsal to this organ, and then lying to the right of 
the stomach follows its outline for a time. Then, entering 
the large venous sinus surrounding the oesophagus, it 
runs alongside and to the right of the latter almost as far 
as the cranial cartilage (fig. 42, Ant. A.). Soon after its 
origin, the anterior aorta gives off a large branch which 
immediately bifurcates into the right and left pallial 
arteries (fig. 42, L. Pall. A.). The right vessel curves 
round dorsal to the aorta, and then runs internal to the 
visceral envelope, towards the funnel retractor. Just 
interior to this it gives off a vessel which runs up 
anteriorly, on the inner side of the visceral envelope, 
giving off several small branches during its course 
(fig. 42, V,H#,A,). This artery, after furnishing several 
small branches to the retractor infundibuli, ends in the 
base of the funnel. The main pallial vessel now runs 
below the posterior part of this funnel retractor muscle, 
and so gains the inner face of the ventral part of the 
mantle, and then runs obliquely to the stellate ganglion 
