64 -LACERTILIA. 
From twenty-one to twenty-four scales in a series along the back* ; scales on the back 
strongly keeled, the keel terminating in a long spine; lateral denticulations may be 
present or absent. The large supraoculars not divided. Length of the hind limb equal 
to, or rather less than, the distance of the vent from the collar; fourth toe longer than 
the head +. Femoral pores varying in number from two to fifteen. The most charac- 
teristic points in the coloration of this race are the light ground-colour of the upper 
parts, be it a greyish or purplish or olive tinge; secondly, a light unspotted band 
running along each side of the back to the root of the tail; thirdly, blackish or 
brownish marbled spots which often are so disposed as to give the appearance of irre- 
gular transverse bands. The throat shows often indistinct blackish longitudinal lines. 
The collar-fold on the side of the neck is generally uncoloured, and in females always 
so; but in very old males from Presidio a blackish patch appears, which extends across 
the throat in the shape of a blackish band, as in Sceloporus viviparus. This latter 
race, however, is never provided with dorsal bands. 
Size of adult male four and a quarter inches without tail. 
The great diversity in the number of pores has given rise to the application of 
several specific terms; but as the several numbers are not accompanied by any other 
peculiar feature, and as they cannot be considered to be limited to certain localities, I 
feel compelled to unite all these specimens under the same heading. 
The following list of localities will show the want of agreement between the number 
of pores and the distribution of the species :— 
Specimens with 2-5 pores: Ventanas (Forrer), Colima (Xantus, in U.S. Nat. Mus. ; 
Mus. Paris), Jalisco, North of Rio Santiago (Richardson), Guadalajara (Cope), Cuer- 
navaca (Mus. Brit.), Vera Cruz (Mus. Paris). 
Specimens with 7-10 pores: Texas (U.S. Mat. Mus.), Sonora (U.S. Nat. Mus.), 
Presidio (Yorrer), Guanajuato (Mus. Brit. & Mus. Paris), Puebla (Mus. Brit.), Atlixco 
(Mus. Brit.). 
Specimens with 12-15 pores: Duval Co., Texas (Taylor), Colorado Bottom (U.S. 
Nat. Mus.), Arizona (W. L. Wright), Mexico (Mus. Brit.), Sonora (U.S. Nat. Mus.), 
Amula and Iguala (H. H. Smith), Tampico (Richardson). 
2. Sceloporus viviparus. 
Sceloporus viviparus, Cope, Proc. Am. Phil. Soc. 1885, p. 898. 
Hab. Mexico, Omilteme 8000 feet (H. H. Smith), Orizaba (Sumichrast), Mirador 
(Sartorius). 
Twenty-two or twenty-three scales in a series along the back; scales on the back 
keeled, with a long terminal spine and a few obsolete lateral denticulations; scales on 
* The scales are counted from a line connecting the two lateral collar-folds to one connecting the hinder 
side of the thighs. I believe thus to obtain more constant numbers than if the scales on the neck behind the 
occiput were included, as these scales are subject to variation in specimens from the same locality. 
t+ Head = distance of upper end of tympanum from end of snout. 
