Atwood—The Viceral Anatomy of the Garter Snake 545 
the food tube lined with small longitudinal folds which project 
into the duodenum. 
The folds of the lining of the small intestine are very complex 
in the duodenum and decrease gradually toward the rectum. 
They do not differ materially from those of the lining of the in¬ 
testine in other snakes. 
The diameter of the tube is greatest in the duodenum and de¬ 
creases gradually toward' the anterior kidney region where it 
reaches its smallest diameter, again increasing toward the ree- 
tum. The intestine becomes very large just anterior to its con¬ 
nection with the rectum. There is a constriction at the junction 
which gives the intestine the appearance of ending in a caecum. 
The lining of the rectum is soft, whereas the outer wall of 
the rectum is. more rigid and comparatively harder. The lining 
of the rectum is a membrane with great surface exposed and is 
extensively folded in order to accommodate itself to the inside of 
the rectal tube. 
The Liver. 
The left lobe of the liver usually extends beyond the right, 
along the vena cava, both anteriorly and posteriorly, but the pos¬ 
terior ends of the two lobes are sometimes equal. In large speci¬ 
mens of T. sirtalis the liver originates about a half inch posterior 
to the heart. In the specimen of T. sauritus sackeni ^he liver be¬ 
gan farther back and was very slender. 
The vena cava is embedded in the ventral surface of the liver 
in all snakes and not in the ‘‘superior” surface as stated by 
Cope (’00). The portal vein is embedded in the dorsal surface. 
The two veins thus divide the liver into two lobes. - 
A large scar occurs on the ventral surface of the left lobe to 
the left of the vena cava and near the anterior end. It is the 
same scar which occurs in Zamenis constrictor and Z. flagelli- 
formis and has been described (Atwood, ’16) as the remains of 
the umbilical vein. Beddard (’06) has described the persistent 
umbilical vein in Boa and Python regius as connected with the 
vena cava direct. 
The liver receives arterial blood from the aorta through many 
hepatic arteries which are also connected with the esophagus. It 
receives venous blood from the portal vein, the epigastric vein, 
the dorsal parietes and the alimentary canal opposite the liver. 
35--S. A. L. 
