Atwood-—The Viceral Anatomy of the Garter Snake 531 
THE VISCERAL ANATOMY OF THE GARTER SNAKE 
William Henry Atwood 
INTRODUCTION 
Our information on the visceral anatomy of the Ophida is 
very limited. Hopkinson and Pancoast (’37) described the vis¬ 
ceral anatomy of the Python, and Jaquart (’55) described its 
circulatory system. Schlemm (’27) studied the circulation of 
Tropidonotus natrix and Trigonocephalus niutus. Broun’s 
Thier Reich (’90) contains a resume of the work up to the time 
it was published. Beddard has contributed much to our know¬ 
ledge of serpent anatomy in his papers published between 1903 
and 1909. O’Donoghue (’12) gave an excellent account of the 
circulation of Tropidonotus natrix. Thompson (’13, ’14) con¬ 
tributed some valuable notes on a number of species. In 1916 
the author described the visceral anatomy of Zamenis Con¬ 
strictor. 
The entire blood system of snakes may be injected through the 
ventricle of the heart. The valves do not prevent the fluid from 
passing, under pressure, into the atria and hence into the veins. 
The vena cava should be injected at the anterior end of the 
liver; the portal vein may be injected at the posterior end of the 
liver when it is desirable to have two colors in the veins. The 
injection fluid used in this work was gelatine colored with lead 
chromate or india ink. 
This paper is based on investigations carried on in the Zoolog¬ 
ical Laboratories at the University of Wisconsin. My thanks 
are due to Professor A. S. Pearse, who read the manuscript. 
