362 PROCEEDINGS OF THE NATIONAL MUSEUM you. 92 
PHRYNOSOMA DOUGLASSII BRACHYCERCUM, new subspecies 
Holotype.—U.S.N.M. No. 23993, from “Durango,” Mexico, collected 
by Dr. Edward Palmer, September 1896. 
Paratypes.—Three topotypes, Nos. 23994-23996, same collector and 
date. 
Diagnosis —Similar to Phrynosoma douglassii, but with a tail 
shorter than head is wide, or, in adults, very slightly longer; gular 
scales in straight rows slightly diverging posteriorly, the scales small 
and tubercular (strongly convex), not flat; chest scales keeled; horns 
cf head very short, postorbitals, temporals, and occipitals subequal in 
s1ze. 
Description of holotype—Head a broad, short, conventionalized 
heart-shape in dorsal profile; in lateral profile, postorbital spines high- 
est, supraocular and internasal areas forming an obtuse angle with 
each other (not a curve) ; width of head (26.2 mm.) at widest point in 
temporal region much greater than length of head from snout to occi- 
put (15.6 mm.) or to posterior tip of temporal spines (21 mm., in a pro- 
jected straight line) ; supraccular region flat, with no enlarged scales; 
posterior border of supraocular region strongly indented medially, 
marked by a series of enlarged, slightly protuberant scales; each series 
begins at postorbital spine and extends anteromedially, but fails to 
reach its mate by 1 scale; postorbital, occipital, and temporal spines 
subequal in size; 5 scales between occipital spines; 2 small, flat spines, 
separated from each other by a scale, preceding occiput; 3 subequal 
temporal spines, the posterior slightly separate from others, the series 
continuing anteriorly as a row of enlarged scales, disappearing below 
about middle of eye. 
Three posterior infralabials considerably enlarged; all labials 
keeled; a series of enlarged, keeled scales in contact with a few 
infralabials anteriorly but separated throughout the remainder of 
its length by one to three rows of small scales; gulars in very defi- 
nite, straight rows slightly diverging posteriorly; these scales not 
flat, but small and convex (tubercular); in extreme posterolateral 
portion of throat the scales are strongly protuberant and conical, 
and have no free lateral edges. 
An irregular series of preauricular spines; tympanum exposed; a 
large skin fold anterior to lateral nuchal pocket, and a small one 
posteriorly, the former surmounted by two series of spines, the latter 
by one or two spines; a small, vertical series of spines in front of 
and above arm insertion. 
All dorsals keeled, imbricate (except enlarged spines), not granu- 
Jar; among these are scattered, enlarged, keeled spines of varying 
size, diminishing laterally; a single row of lateral spines (fringe) ; 
in the posterior part of fringe the spines are separated from each 
