182 THE EEPTILES OF EGYPT. 
the Luxor district. In the exception the disk consists of three pieces. Disks of this 
kind also occur at Beni Hassan in Middle Egypt. Two out of 4 specimens from 
Medinet Habu conform to the Luxor type of disk, one to the form found at Suez, 
Maryut and Heluan, while in the fourth the disk is divided into two lower and two 
upper pieces. At Assuan and Phila? the formula is g, as at Suez &c. At Durrur 
seven out of eight have the disk consisting only of two pieces, as in the Luxor 
specimens, while in one it is broken up into as many as 7 pieces, thus - b - This 
much divided form of disk also occurs in the only two specimens I have from Suakin, 
in one from Erkowit, and in another from Akik. 
Out of 52 specimens from the foregoing Egyptian localities, 37 have the palpebral 
disk divided in two vertically, while 15 have it composed of more than that number; 
hence the former number, from its prevalence, may be regarded as distinctive of Egypt, 
but more especially of Upper Egypt and the Eastern Sudan. It is also found in 
lizards from Baluchistan, Eastern and South-eastern Persia, Afghanistan, and Turkestan. 
In Sind, the upper half of the disk is divided into two unequal pieces, the anterior of 
which is twice as large as the posterior, and has below it a piece of nearly its own 
length, while a small portion is interposed at the point where they meet ; but in other 
lizards from the same locality the palpebral disk resembles that prevailing at Heluan 
and the plain of Suez. There are still, however, further modifications found in Sind, 
but they follow much the same kind of division as is present in the Suez example. 
At Gabes, in Tunisia, a form of disk different from all the foregoing is met with, as 
it consists of four pieces, an anterior and posterior and a superior and inferior, more or 
less symmetrical in then disposition and size ; on the other hand, at Susa, in the same 
region, the disk is divided into six nearly equal-sized pieces, the posterior portion the 
largest and common to the upper and lower sections of the disk, with two pieces 
anterior to it superiorly and three inferiorly. Disks of nearly the same type are met 
with at Laghouat and at Tuggurt, and they are only slight modifications of what 
occurs at Medinet Habu, which is also the case with the disk of the Morocco lizards 
described by Boettger as E. simoni. Ten examples from Tunisia, the Algerian Sahara, 
and Morocco have been examined by me, and in only one of them, viz. a specimen 
from Tibremt, is the disk composed of two pieces, as in lizards of Upper Egypt ; in 
all the others it is broken up into three or six pieces. A nearly similarly divided 
palpebral disk is found in the Socotran variety. 
From the foregoing facts it is evident that the division of the palpebral disk is 
the subject of great variation. It is most stable in Upper Egypt, the Eastern Sudan, 
Persia, Baluchistan, Afghanistan, and Turkestan, and most variable in Lower Egypt, 
the Sinaitic Peninsula, Arabia, Syria, Tunisia, the Algerian Sahara, Morocco, Socotra, 
and Sind. 
