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THE MAMMALS OE EGYPT. 
Lichtenstein in 1823 ^ gave a short description of two species of Egyptian jerboas, 
viz. Dipus Mpes and D. hirtipes, the former said to inhabit Egypt, and the latter the 
Desert of Sakkarah; the first was the animal originally described by Olivier, and the 
second that first described by Hasselquist. 
In 1828, in his Monograph of the Springmduse Lichtenstein indicated two species 
from Egypt—the one under the name D. cegyptius, Hempr. & Ehrenb. (which was 
most probably a manuscript name of these authors, as I have not been able to find in 
their writings any jerboa described by them under this term), and the other as 
]). hh'tipes', the former being the larger and corresponding to his D. hipes, a term 
which does not occur in his Monograph, and the other the smaller species already 
indicated by him in 1823. It is evident from Lichtenstein’s description of the feet of 
D. ceqypiins that it is not the Mus jaculus, Linn., but the jerboa of Olivier, which this 
traveller says was regarded by the ancients and moderns as a biped animal. Olivier saw 
it frequently in the environs of Alexandria, just as I have observed it there a century 
later, and the description in the third volume of his ‘ Travels ’ leaves no doubt whatever 
of the identity of his Dipus gerhoa. 
Over the bare area of the nose of Jaculus there is a thickened fold of skin capable of 
being drawn forwards so as almost to cover the nostrils, this structure serving to protect 
them when the animal is using its broad snout to push out the earth when making its 
burrow. 
One of the leading features of the skull of Jaculus is the great size of the infra¬ 
orbital foramen and the development of the preorbital wing-like processes of the malar 
surmounted by the expanded lachrymal. These modifications of the area in front of 
the oibital cavity have reference to the habits of the animal, and serve to protect the 
eye when the head is used to shovel out the soil from its burrows. The digging is 
done by its seemingly feeble anterior extremities, the loosened sand being swept 
back by the brushes of the hind feet. 
The skulls of the two species manifest the same differences that are observable in 
the head of the living animal, namely, the greater breadth across the conjoint areas of 
the infraorbital foramina, and also the greater interorbital breadth in the larger 
as compared with the smaller species. The difference in the size of the two species is 
also well exemplified in the dimensions of their skulls in the adult state. 
[Notices of the jerboa date from the earliest historic times, Herodotus, Theophrastus, 
and Aristotle being among the earliest writers. Bruce has an excellent chapter on the 
subject in his ‘Travels.’ Sonnini (Voy. Egypte, i. 1798, chap. xi. p. 156) gives a most 
complete anatomical description of the animal, and preceded Olivier in noticing the 
extraordinary armature of the glans penis of the large species. 
1 Terz. Doubl. p. 5. ^ Abhandl. kbnigl. Akad. Berk 1828, pp. 151,152. 
