Ativood—The Viceral Anatomy of the Garter Snake 533 
I believe that the forms with the lateral line on the second 
and third scale rows and those with the lateral line on the third 
and fourth scale rows {T. radix and T. sirtalis) are interbreed¬ 
ing in this locality. No. 4 and No. 7 have the lateral stripe in 
the third and fourth scale rows {T. radix). No. 9 has the lat¬ 
eral stripe on the third row and some color on the second and 
fourth rows. This suggests T. butleri, but the scutellation has 
not been reduced enough to fit that species. The sides of this 
specimen were marked with two rows of black spots divided by 
yellow. The yellow also appeared on the scales slightly. I 
therefore judge this specimen to represent the yellow phase of 
T. sirtalis parietalis although it differs from the type specimen 
and its known range does not include this locality. Nos. 6 and 8 
were very much alike (T. sirtalis). In No. 10 (T. sirtalis) the 
stripes were all very broad, those on the sides covering the first 
scale row. The specimens from Marion County, Florida, (Nos. 
11, 12, 13, 14, 15, 16, 17,— T. sirtalis) were alike in color, hav¬ 
ing prominent black spots on a light blue background. Specimen 
No. 18 from Marion County Florida, was a typical T. sauritns 
sackeni. 
Circulatory System. 
The Arteries of the Neck. 
Three arteries leave the right aortic arch to supply the body 
anterior to the heart. The left carotid artery lies dorsal to the 
left jugular vein and ventral to the esophagus; supplies the left 
thymus gland, the thyroid gland, the fat body, the esophagus, 
the trachea and the head. Its branches are all very small and 
variable in the neck region. 
The right carotid artery has been reduced to the small thyroid 
artery of O’Donoghue (T2) {ramus glandularis of Brown, ’90). 
It supplies the thyroid gland and in some specimens sends a 
large branch to the esophagus. This esophagaegal branch passed 
dorsal to the heart and ran caudalward along the ventral wall 
of the esophagus, (Fig. 1). It was found by the writer (’16) in 
Zamenis constrictor and its root was figured but its course could 
not be fully traced, hence it was not described. I do not know 
that it has been mentioned before or that it exists in all speci¬ 
mens of the species herein considered. Twigs from the thyroid 
! 
