AGAMA PALLIDA. 103 
Tbe uniformity or nearly so of these small scales that form the groundwork, so to 
speak, of the lepidosis is one of the features by which A. pallida can be distinguished 
from A. mutabilis, in which the scales of the general lepidosis are much more irregular 
in size. These small scales are generally devoid of keels, but they are occasionally 
keeled here and there. Variations in the lepidosis are sometimes observable in 
which it is not so uniform, but uniformity prevails compared to the diversity present 
in A. mutabilis. Scattered in a varying degree among this groundwork of small scales 
occur keeled enlarged scales, some larger than others. On the upper surface of the 
fore and hind limbs the scales are carinate and imbricate, with an intermixture of 
enlarged scales. The ventrals are smooth, pointed or divided at their tips, and are 
about the same size as the scales of the sides of the body. 
The tail is covered above with keeled pointed scales, slightly larger than the largest 
of the ordinary scales on the middle of the back. The limbs are well developed and 
the fingers and toes are only moderately long, and the claws of the fore feet are well 
developed and larger than in the hind foot. 
Notwithstanding the differences I have attempted to indicate as existing between 
A. 'pallida and A. mutabilis, they are so closely allied that I am not confident they may 
not ultimatelv be united by the study of larger materials. 
I subjoin a table (p. 104) giving the details of measurements &c. of the specimens 
that have come under my observation. 
Out of the 44 specimens enumerated, 33 have the skull longer than the tibia ; but in 
17 of them the excess in each case is less than a millim., and in 13 less than 2 millim., 
and only in two more than 2 millim. Six of the 44 have the tibia and skull equal, 
while in five the tibia is longer than the skull, but only to the extent of 1 millim. 
or so. 
A single line of praanal pores is rare, and when the number of lines exceeds two the 
transverse arrangement of the pores is not very regular, and they may not be continuous 
from side to side. 
There are variations in the colour that explain the origin of the terms leucostigma 
and nigrofasciata applied by Eeuss to examples of this species from Upper Egypt and 
Nubia. For example, in a specimen from the east of Suez there is a dark bar on the 
upper surface of the head, between the eyes, one across the occipital region, another 
on the neck, a fourth on the body behind the shoulders, a fifth across the middle of 
the back, a sixth on the loins, and 14 black bars on the tail. A white spot occurs in 
the centres of the three essentially dorsal bands. When these spots are not very 
prominent we have nigrofasciata, and when they are very distinct leucostigma. 
In 1823, Lichtenstein l gave a short diagnosis of an Agama from Egypt, which he 
called^, deserti ; but his description is so imperfect that it is impossible to reconcile it 
1 Verz. Doubl. Ber. Mus. 1823, p. 101. 
