JACULUS. 
30:5 
urging the Bedouins to bring to me all the mammals they knew to occur in the neigh¬ 
bourhood of the Pyramids, the only jerboa I obtained from them was the smaller 
species. It was not until I had commenced my observations on the fauna around 
Alexandria that I became acquainted with the larger species, which is there even more 
abundant than the smaller form is at Gizeh, but the latter I never observed at 
Alexandria. If the larger species does not occur at the Pyramids, then there can be no 
doubt whatever that Mus jaciihis, Linn., is the smaller Egyptian jerboa. 
Olivier \ while in Egypt, directed his attention to the jerboa found in the environs of 
Alexandria, which he described under the name Diims gerhoa Numerous examples 
of a large jerboa, common in the country surrounding Alexandria to the east and west, 
on high land beyond the direct action of the Nile inundations, were examined by me 
and were frequently dug out of their burrows on the stony low hills about Pamleh. 
Ihis species is undoubtedly the Dipus gerhoa of Olivier, and is the only species of the 
genus, as far as I could ascertain, that occurs in that part of the Delta of the Nile. It 
is very much larger than the smaller species of the outskirts of the Libyan Desert at 
the Pyramids of Gizeh ; and when fceen at rest, seated on the ground, with its body 
drawn together, it reminds one of a diminutive hare in its general colour, form, 
and large ears. 
Olivier fortunately described some parts of the anatom\ of this animal, and among the 
features which caught his attention as being remarkable, which it certainly is, was the 
formidable armature of the penis, the dorsum of the glans being provided with two 
remarkable curved horny spines, measuring 9 mm. in length, the rest of the glans 
being covered over with spines of varying sizes. In the smaller form from Gizeh the 
structure of the glans penis is entirely different, as it is destitute of spines, and, indeed, 
so far from being armed with such structures, it is covered with a multitude of minute 
pits, in each of which lies a small scale, adpressed to the bottom, but with a toothed 
free border. The glans itself also differs in the form of its lobes, and by this structural 
difference the two species are sharply defined one from the other. 
The first figure of the large species was published a few years after Hasselquist’s visit 
to Egypt. It is found in Edwards’s ‘Gleanings of Natural History’^, where we are 
told that it is a life-sized representation of the species. This figure, although very 
imperfect from an artistic point of view, is still undoubtedly intended for the larger 
species ; it was drawn from a specimen living in London, and it was probably from 
this figure that Pennant^ derived his knowledge of the Egyptian jerboa, although in 
his synonymy he did not distinguish between it and the smaller species. 
1 Voyage dans TEmpire Ofchoman, t. ii. (180t) pp. 42, 43. 
2 Bull, de la Soc. Phil. t. ii. 1801, p. 121. 
^ Vol. V. 1758, pp. 18-19, pi. 219. 
4 Hist, of Quad. vol. ii. 1793, pp. 164-166, 
