118 THE REPTILES OF EGYPT. 
to it in the proportions of its digits, as in both the third finger is longer than the 
fourth ; this proportion, however, is reversed in the corresponding digits of the pes. 
Fingers with these proportions are met with in A. smithii and A. lionotus, whereas 
in A. bibronii, A. hartmanni, A. colonorum, and A. spmosa the third and fourth fingers 
are equal, but occasionally the equality is not well defined in the last-mentioned 
species, and in it third fingers are met with that are longer than the fourth, so that 
much importance cannot be attached to the relative length of these fingers in this 
group. 
A. smithii, Blgr., is only known from a single female. It is closely allied to 
A. spinosa, Gray, on the one hand, and also to A. rueppellii, Vaillant. A. lionotus, 
Blgr., is related in some respects to the South- African A. planiceps, but at the same 
time differs from it very materially — e. g., its short and stout digits, feebly keeled dorsal 
scales, and larger rosettes on the sides of the head and neck. A. lionotus was 
obtained at an elevation of 2400 feet above the sea, close to the eastern side of the 
southern end of Lake Rudolf; and A. smithii 400 miles to the west between the 
Shebeli and Juba rivers, at an elevation of 700 feet 1 . 
A. lionotus ( 6 ) is provided with a remarkably large scute at the base of each claw. 
It will be observed from PL X. figs. 2 & 3 that a similar scute is present in A. spinosa, 
and that it is much more developed in the male than in the female. In the female 
A. smithii this scute is very small ; but whether the females are always distinguished 
by a small and the males by a large ungual scute remains to be ascertained. The 
differences manifested by the sexes of agamoid lizards emphasize the necessity of 
accurately ascertaining the sexes of individuals described as new species by the actual 
inspection of the internal organs of generation, as it is impossible to place reliance on 
the absence or presence of prsanal pores, or on the degree of development of femoral 
pores as'a guide to sex. 
The degree to which the tail is verticillated in the A. colonorum group varies 
considerably. In none of them do the verticils embrace the entire base of the tail as 
in A. stellio and A. zonura, Blgr. ; but these two species are linked to a certain extent 
with A. colonorum and its allies by such species as A. annectens and A. adramitana. 
I have mentioned the foregoing members of the A. colonorum group, as it is 
possible that some of them may be found to enter the Nile valley in the direction of 
Wadi Haifa. 
1 Through unknown African Countries (A. Donaldson Smith), 1897, Eoute Maps. 
