• [157] CEPHALOPODS OF NORTHEASTERN COAST OF AMERICA. 
anterior end of a thin, median, membranous partition, supplies the ven¬ 
tral and lateral portions of the mantle, sending branches both back¬ 
ward and forward; the other two main divisions (o', o") diverge as they 
go backward, and supply the caudal fins and adjacent parts of the 
mantle. The anterior aorta ( ao) arises from the right anterior corner of 
the heart, and goes forward to the head, on the right side of the 
median line, by the side of the oesophagus. Just beyond the constric¬ 
tion, at its origin, it is somewhat bulbous. A short distance from its 
origin it gives off a large branch, the gastric artery (so), which sends a 
branch to the renal organs, and passes backward over the dorsal side of 
the heart to the anterior parts of the stomach, where it ramifies exten¬ 
sively. 
The portion of the aorta which passes along and through the liver 
gives off several hepatic arteries that supply blood to the liver, and one 
branch emerges from the liver, on the dorsal side, and supplies the 
muscles of the neck-region. The ultimate divisions of the aorta supply 
the various organs of the head, and a large branch goes out to the tip 
of each arm, nearly in the center, sending branches to the suckers. A 
small vessel, the spermatic artery (fig. 2, go), arises from the anterior 
side of the heart, and, passing backward over the heart, supplies the 
spermary ( t ). 
The large efferent or branchio-cardiac vessels from the gills (bo) 
enter the anterior lateral corners of the heart, their dilated basal por¬ 
tion serving, apparently, as auricles. The branchial auricles (au), situ¬ 
ated just behind the bases of the gills, are nearly globular, with a 
small, rounded, whitish elevation on the free posterior end; anteriorly 
they receive the blood from the sacculated divisions of the anterior 
and posterior vense-cavse, above the heart, and from the veins (v, vc') 
coming from the lateral portions of the mantle, behind the gills, and 
they give off the large afferent vessels (bv), which go to and run along 
the dorsal side of the gills. The anterior vena-cava (vc) receives the 
venous blood from a large cephalic venous sinus * which surrounds the 
pharynx, at the bases of the arms, and is also directly connected with 
another large sinus at the back of each eye-orbit. This cephalic sinus 
receives the blood from a large vein in the median line and near the 
iuner face of each arm. The ophthalmic sinuses receive veins from the 
eye itself. Numerous small veins enter the anterior vena-cava , from 
each side, along its course, coming from the muscles of the head, neck, 
and siphon, and from the ink-sac, fiver, &c. Two veins, sacculated 
posteriorly, go from the ink-sac and intestine back to the renal organs. 
A small but very distinct vein extends along the dorsal side of the 
efferent sperm-duct (p). Two large pallial veins, on each side, come 
* Tlio greater part of the venous system can be easily injected by inserting the 
canula into this sinus, through the folds of the buccal membranes, just between the 
bases of the arms and the jaws, or between the outer and inner buccal membranes. 
It can also be easily injected through the vena-cava in the lower side of the head. 
