ANATOMY OF THE BEAVER. 
S49 
Danube, and which, added to the general resemblance of 
their respective anatomical structures, would lead us to 
suppose that those of Europe and America belong not only 
to the same species, but even to the same variety. The 
specimens were so far mutikted, as to prevent any exami- 
nation of the head and organs of sense contained therein. 
I observed, however, that the Beaver resembles many of 
the Rodentia, in having hairs growing on the inside of the 
mouth, near the angles ; these perfectly resemble the hairs 
covering the integuments. 
As both animals had died of inflammation of the intes- 
tines, producing, in one case, an extensive intus-susception, 
I found it impossible to make minute researches either into 
the structure of the internal tunic, or into the exact distri- 
bution of the bloodvessels. That which appeared to me 
most remarkable in the sanguiferous systems of the abdo- 
minal viscera, was the presence of an extensive sinus, 
or receptacle for the blood, situate close to and above the 
liver, at the point where the peritoneal coat is reflected 
from the abdominal surface of the diaphragm upon that 
organ. Into this horizontal sinus entered the hzver cava 
and hepatic veins, and from it arose a single trunk convey- 
ing the Wood into the right auricle of the heart ; the dia- 
meter of which trunk certainly did not exceed that of the 
abdominal cava, immediately on its receiving the renal 
veins. The foramen ovale of the heart was closed, and the 
ductu^i arteriosus converted into a ligament. The Eusta- 
chian valve was very perfect ; and another similar valve 
was found at the entrance of the superior cava into the 
right auricle of the heart. 
The ductus communis choledocus and pancreatic duct 
entered the intestines at a distance of about 14i inches 
from each other. The physiology of this part of the struc- 
ture of animals is not at all understood. In general, ho^v- 
