ANATOMY OF THE OPHIDIA. 381 
terminates two gastrosteges further on, and is without an intra- 
pulmonary prolongation. The tracheal membrane is bare to a 
trifle above the base of the heart,at which point it acquires a thin 
lining of shallow-celled respiratory tissue. The right lung is lined 
with air-cells to the level of the 55th g. There is a free apex 
reaching forward for the distance of two gastrosteges and in 
relation with the right side of the trachea. The left lung is 
entirely suppressed. The heart apea is at the 38th, and the tip 
of the liver at the 50th g. 
There are 144 gastrosteges. The scales are in 17 rows anteriorly 
and the same posteriorly. — . 
PoLYODONTOPHIS COLLARIS Gray. 
Specimen.—California Acad. Sci. No. 26783. Mo Kan Shan, 
Chekiang Prov., China. Adult male. 
The tracheal membrane begins to be lined with respiratory 
tissue a little before the base of the heart. The trachea enters 
the lung at the level of the 38th g. The right lung is lined 
with respiratory tissue to the 60th g. There is a free apex 
3 mm. long in relation with the right side of the trachea. 
The lefé lung is entirely suppressed. The heart apex is at the 
level of the 36th and the tip of the liver at the 54th g. 
This is an unusually long distance between these organs, as the 
average of a Colubrine serpent is about ten gastrosteges, The 
points of all the teeth on the maxillary, palatine, and pterygoid 
bones are brown. The mandibular teeth are not in the normal 
alignment ; those in the anterior third of the series are abruptly 
faulted inwards, so that they are set in about ‘7 mm. from the 
line of the remaining teeth. 
There are 172 gastrosteges. ‘The scales are in 17 rows anteriorly 
and the same posteriorly. 
THAMNOPHIS ORDINOIDES Baird & Girard *. 
The salient character is the range of variations that occurs in the 
number of scale-rows. A series of over one hundred specimens 
has been studied, and the following eight formule recorded :— 
21-19-17, that is 21 rows forward, decreasing to 19, and further 
along to 17; 19-21-19-17, that is 19 rows forward, increasing to 
21 at about the level of the heart and continuing to the end of 
the liver, then decreasing to 19, and further on to 17; 19-17; 
19-17-15; 19-17-15-13 (13 is the lowest number of scale-rows 
on the body that has been recorded in Zhammophis); 17-19-17— 
15; 17-15; 15-17-15; these lower counts prevail in specimens 
from the State of Oregon. 
* According to the classification of the North American Garter-snakes as set 
forth by A. G. Ruthven, Esq., in his memoir, “ Variations and Genetic Relationships 
of the Garter-snakes,” 1908, Bulletin 61, U.S. National Museum, this species 
includes Tropidonotus leptocephalus (B. & G.) and T. vagrans (B. & G.). 
