STENODACTYLTTS. 41 
In specimens from the delta of Egypt and from the Eastern Sudan both the upper 
and the lower labials fall as low as 10 and rise to 13. 
The gecko described by Guichenot as mauritanicus is more stoutly built than the 
Gizeh geckos, and its head is somewhat heavier and slightly broader, whereas the type 
of S. wilMnsonii in its general form resembles the Gizeh sand-geckos. 
In the delta of the Nile, near the sea, geckos with the heavier body of mauritanicus, 
and with its short and stout limbs and digits, are present (PI. IV. fig. 5) ; but at Luxor 
(fig. 3) individuals of this type occur, but with more slender limbs and digits, and with 
the nostrils of wilMnsonii (fig. 4). These seem to link the Algerian geckos to those 
of Gizeh. On the other hand, individuals are met with (fig. 6) in the Eastern Sudan 
(Durrur and Suakin) which must be regarded as intermediate between those of the 
Nile delta and those of Algeria. 
It is noteworthy that the skin of the geckos of the Nile valley proper is not so 
coarse as that of those inhabiting Algeria and the seaward face of the delta, both of 
which areas are exposed to the storms of the Mediterranean ; and that similar differences 
exist in the genus Ptyodactylus, in which Syrian and Algerian specimens have harder 
and coarser skins than those found in Egypt. 
After a careful consideration of the foregoing facts in all their aspects, the safe 
conclusion seems to be that the specimens here dealt with are all referable to one 
species, viz. S. elegans, Fitz., as the variations they manifest are so unstable as to 
be beyond the reach of clear definition. 
The gecko from Bou-Saada obtained by M. Lataste I consider to be identical with 
two specimens from Batna recorded by Strauch, and referred by him to S. wilMnsonii, 
Gray. Since 1885, the British Museum has become possessed of two geckos from 
between Batna and Biskra, identical with the specimen from Bou-Saada. Mr. Boulenger 
informs me that they were part of the same collection from which Strauch obtained 
his Batna lizards. On comparing them with Strauch's description of the Batna lizards, 
it is apparent that they are one and the same species, and quite distinct from 
S. wilMnsonii, Gray, = S. elegans, Fitz. I believe them to be identical with the 
species I have described as S. petrii. Consequently the two species exist side by side 
in Algeria, as they do on the plain of Tel el Amarna, in Egypt. 
