Atwood—The Viceral Anatomy of the Garter Snake 539 
veins course forward along the sides of the cloaca and pass 
along the ventral edges of the kidneys to their anterior end, but 
do not pass beyond this point as they do in the Boidae (Bed- 
dard, ’04, ’06, ’08). As in other snakes these veins receive 
blood from the region of the anus and vagina, sperm ducts or 
oviducts, epigastric vein and from the dorsal parietes. The con¬ 
nections between the afferent renal veins and the vein of the 
fat body are not prominent and could not be made out. The 
iliac veins are very prominent in Thamnophis. They carry 
blood from the body wall on either side of the anus to the affer¬ 
ent renal veins. They have no connection with the abdominal 
or epigastric veins. They were described in Tropidonotus na- 
trix by O ’Donoghue (’12) as the pelvic veins, and in Zamenis 
constrictor by the writer (’16). 
The afferent renal veins. AR, afferent renal veins; CV, caudal vein; 
ER, efferent renal vein; EV, epigastric vein; IV, illiac veins; LK, left 
kidney; MV, mesenteric vein; OS, oviducal sinus; PV, parietal veins; 
RK, right kidney; X, abnormal connection between the efferent and 
afferent renal veins. 
In the specimens observed from three to five veins leave the 
dorsal parietes of each side and enter the afferent renal veins 
before they reach the kidneys. In specimen No. 1 a vein from 
the parietes of the left side entered the afferent renal vein of 
that side just posterior to the kidney. Just before this parietal 
vein entered the afferent renal vein it gave off a large branch 
which entered the efferent renal vein. Thus permitting the 
blood to pass from the afferent renal vein to the efferent renal 
vein directly, without first passing through the kidney, (Figs. 
3, 4). A similar condition was observed on the right side in 
