62 LACERTILIA. 
2. Uta irregularis. 
Phymatolepis (Uta) irregularis, Fischer, Abhandl. nat. Ver. Brem. vii. 3, 1882, p. 282, t. 17. 
figg. 1-4; Boul. Cat. Liz. 1. p. 216. 
Hab. Mexico, Highlands. 
I have not examined a specimen of this species. 
8. Uta bicarinata. 
Phymatolepis bicarinatus, A. Dum. Arch. Mus. viii. p. 549, t. 23. fig. 2; Bocourt, Miss. Sc. Mex., 
Rept. p. 165, t. 17 bis. figg. 9, 9a, 6; Sumichrast, Bull. Soc. Zool. v. 1880, p. 176. 
Uta bicarinata, Cope, Proc. Ac. N. Sc. Phil. xvi. p.177 ; Boul. Cat. Liz. ii. p. 215; Cope, Proc. Am. 
Phil. Soc. 1885, p. 379. 
Hab. Mexico, Presidio, Ventanas, Ciudad in Durango (forrer), Cuernavaca, Matamoros 
Izucar (Ferrari- Perez), Puebla (Boucard), Jalisco, North of Rio Santiago (Richard- 
son), Tehuantepec (Sumichrast). 
An arboreal species according to Sumichrast. 
SCELOPORUS. 
Sceloporus, Wiegmann, Isis, 1828, p. 369. 
Tropidolepis, Cuvier, Régne Anim. 2nd edit. ii. p. 38. 
The Reptiles of this genus are, after the Anoles, the most numerously represented 
type of Lizards in Central America. Northwards they extend far into the United 
States, but southwards they have not been found beyond the limits of Central America. 
Sumichrast writes about the Mexican species observed by him as follows :—‘* The 
Scelopori are natives of the Central Tablelands and Alpine districts, comparatively few 
being found on the warm plains of the coast. On the eastern or Atlantic side Scelo- 
porus variabilis is the only one which is to be found in the tierra caliente of Vera Cruz. 
On the Pacific side of the isthmus of Tehuantepec I collected but three species, viz., 
Sceloporus variabilis, S. melanorhinus, and 8S. siniferus. In the vicinity of Orizaba 
(Vera Cruz), but to a height varying between 1200 and 2500 metres, Sceloporus 
malachiticus, formosus, microlepidotus, and scalaris are to be found. Others, as Scelo- 
porus horridus and S. eneus, are at home on the dry and sterile plains of the plateau, 
and people, with Rattlesnakes and Tapayaxins (Phrynosoma), the rugged lava deposits 
known as malpaés (bad lands) or the monotonous fields of Agave. Although most of 
the species are strictly humivagous lizards, others dwell in trees, and spend most of 
their life in them : such is the case with Sceloporus melanorhinus and some others.” 
Many of the species, perhaps the majority, are ovoviviparous. 
No other genus of Lizards offers greater difficulties in distinguishing the numerous 
species, races, or forms, and these difficulties are almost insurmountable when it is 
attempted to take into consideration species vaguely defined and without distinct indi- 
cation of the locality where the type was found. But little difficulty is met with when 
