xliv INTRODUCTION. 
Owing to its fertility and geographical position, an investigation of its fauna would 
probably yield interesting results. 
Before leaving the oases of the Libyan desert, the Fay urn and the Wadi el Natrun 
require to be noticed. The first of these depressions is surrounded by the desert, 
except at the point where the Bahr Yusuf enters it, but the interspace is so narrow, 
being not more than four to twelve kilometres in breadth, and the intervening heights 
are so low, that the Fayum may be considered as a part of Egypt proper, so far as its 
zoology is concerned ; and, in connection with this, the Fayum is interesting as being 
the northern limit to the distribution of the egg-eating snake, Basypeltis scabra. It is 
in no sense isolated from the valley of the Nile, as the course of the Bahr Yusuf is 
marked by cultivation linking its fields with those of the Nile. 
The valley of the seven or eight permanent Natron lakes, visited by Browne in May 
1792, and seven years later described by Andreossy 1 , is separated from the Nile by a 
shingly desert about 39 kilom. in breadth. It is usually approached from near Teraneh, 
and when the road reaches the low-level summit of the undulating plateau which 
slightly ascends towards the west, it at last begins to descend to the ridge of the valley 
which is of no great height. The depression in which these lakes, ponds, and shallow 
morasses are situated is supposed to lie below the level of the Nile. It is 36 kilom. 
long and is about 12 kilom. in its broadest part, but the actual plain, which is more or 
less covered with low isolated hills and banks of sand, is much narrower. The water 
in the shallow basins begins to rise towards the end of September, and continues to 
do so until the end of December, but in summer many of the smaller basins completely 
dry up. During the foregoing period the water oozes up on the eastern side of the 
valley and flows down to the basins in blood-coloured streams due to the presence 
of some minute organisms. A certain amount of water is also supplied to them by 
the winter rains. Browne states that no vegetation w r as visible during his visit except 
the reeds on the margins of the lakes ; but Wilkinson 2 , in 1842, found that, although 
the valley possessed no trees, the usual plants of the desert, including some tamarisk 
bushes and stunted palms, were also present, besides reeds and rushes deriving their 
support from springs of fresh water. 
An antelope and the ostrich were, according to Browne, the only wild animals that 
frequented that part of the country in his time, but Wilkinson mentions the presence in 
the Natron valley of a gazelle (1 G. Ifjatoceros), a jerboa, and foxes, besides a few of the 
other common animals of the Libyan hills. In James Burton's manuscripts in the 
British Museum, the interesting fact is recorded that Trionyx triwnguis existed in the 
waters of the Natron Lakes. If this observation was correct, it is of considerable 
importance, as it may be inferred from it that the Wadi el Natrun had been at some 
period of its history in direct relation with the Nile. The chameleon is said to occur- 
in the valley, and very explicit statements have been made by some of my informants 
as to the presence of the wild pig on its sedgy ground. 
1 Mem. sur l'Egypte, i. (1799-1810), p. 223. J Journ. Geogr. Soc. 1843, p. 113. 
