MEXICAN HERPETOLOGICAL MISCELLANY—SMITH 363 
other, while anteriorly they are in contact; spines on tail few, small; 
tail very broad at base, but remainder very slender, not tapering 
into base; eight longitudinal series of spines at base of tail. 
Scales on chest rather distinctly keeled; remainder of ventral 
scales smooth; femoral pores 16-18; 14-16 lamellae under fourth toe. 
Total length 80 mm.; tail 24 mm. 
Head shghtly reddish; body dirty straw yellow, with transverse, 
median, dusky (gray) crossbands; limbs feebly barred; throat, chest, 
and sides of abdomen with small, round, scattered dark spots. 
Variation—The three paratypes are much as the type. All have 
convex gulars, although some of the scales show edges. The keels 
on the chest scales are very evident even in the smallest specimen. 
Measurements (in millimeters) of d. brachycercum 
Percent,| Percent, 
Snout Head . < 
Catalog number Sex 3 ac Tail tail of head of 
to vent | width body tail 
WSINSMe- 23993. 22. 2 9 80. 0 26. 2 24. 0 30. 0 109. 1 
U.S.N.M. 23994______ Q 7150 24. 0 23. 0 32. 4 104. 3 
WES sNEM. 23095-2222 o) 38. 7 12.8 10. 0 28. 7 128. 0 
US.N-M. 23996. __.2- Q 71.0 22. 8 23. 0 32. 4 99. 1 
Comparisons—These four specimens appear to represent a race 
closely related to douglassii and its subspecies. The ludicrously short, 
slender tail attached to a broad base readily characterizes it, and is 
the chief difference between it and other races of douwglassii. The 
convex gular scales and keeled chest scales also appear to be peculiar to 
d. brachycercum. 
In 74 specimens of other races of dowglassii (including 15 whose 
measurements are given by Van Denburgh, Rept. Western North 
Amer., 1922), the tail varies from 36.1 to 65.2 percent of the body 
length, average 47.5; sexed specimens show a range of from 36.1 to 
53.2 percent, average 45.4, in females, 44.1 to 65.2 percent, average 
51.4,in males. ‘The width of the head varies from 36 to 92.4 percent 
of the tail length, average 65.1; sexed specimens show a range from 
53 to 86.9 percent, average 67.3, in females, 48.6 to 80.2 percent, 
average 62.0, in males. 
38.—A TENTATIVE ARRANGEMENT AND KEY TO MEXICAN GER- 
RHONOTUS, WITH THE DESCRIPTION OF A NEW RACE 
A survey of the Mexican Gerrhonotus in the United States Na- 
tional Museum has revealed the existence of a much greater var- 
iability in certain characters in scutellation of the head than has 
heretofore been known. Of surprising variability is the azygous 
