Atwood—The Viceral Anatomy of the Garter Snake 541 
parietes of /either side, take their way in the mesentery of the 
ovary for a short distance, and then enter the adrenal bodies; 
or they may enter the adrenal bodies direct. They often re¬ 
ceive branches from the longitudinal vein of the oviduct before 
entering the adrenal body. This adrenal portal system has been 
mentioned as existing in several snakes and is probably present 
in all members of the order. (Ecker, ’46; Gratiolet, ’53; Bed- 
dard, ’04; Atwood, ’16). 
From eight to twelve veins enter the vena cava from the 
ovaries and oviducts bet^yeen the kidneys and the liver, some 
entering posterior to the adrenal bodies. These veins all con¬ 
nect the vena cava with a long sinus in each oviduct, which 
originates from the afferent renal vein of the same side and 
runs along the oviduct to the anterior end where it enters the 
vena cava, (Fig. 4). This ovidncal sinus was first described by 
O’Donoghue (T2) in Tropidonotus natrix. It is not prominent 
except when the oviducts are filled with developing eggs. This 
probably accounts for the fact that it has been overlooked until 
recently. 
The region between the adrenal bodies and the liver is 
drained by the portal vein. The vena cava receives no branches 
in this region except from the structures connected with repro¬ 
duction. It passes along the ventral surface of the liver on its 
way to the sinus venosus, receiving blood through the capillaries 
of the liver from the portal vein, the dorsal parietes, the epigas¬ 
tric vein, the stomach and esophagus. All of the blood from the 
posterior part of the body enters the heart through the vena 
cava except that from the lungs. 
The Portal Vein 
The portal vein originates as the inferior mesenteric vein from 
the rectum and from branches from the right and left afferent 
renal veins. This vein runs along the intestine, but does not 
follow its folds very closely. After its origin the mesenteric 
vein receives no branches other than those from the intestine 
until it is joined by the abdominal vein of the fat body. These 
two veins are of about equal size and unite about one inch cau¬ 
dal to the pancreas. 
In the specimens examined no veins from the parietes entered 
the portal vein posterior to the pancreas as is the case in Zamenis 
