JACULUS JACULUS. 
305 
The synonymy of the Jerboas is very complicated, for none of the earlier writers 
distinguished between the different species, and even embodied the five-toed Alactaga 
in their descriptions. The synonymy given below for the several species is confined 
to notices relating more particularly to specimens from Egypt. Lataste identifies 
certain Jerboas from Algeria and Tunisia with the Egyptian species, setting aside names 
which had been bestowed on these local forms, but the absolute identification should 
be received with caution. At the same time it may be remembered that Jaculus 
mauritanicus^ Duvernoy (Mem. Soc. Hist. Nat. Strasb. iii. 1842, p. 30), from Oran, is 
allied to Jaculus orientalis, Erxl., and Jaculus desertii, Levaillant (Loche, Explor. 
Alger. 1867, p. 100), to J. jaculus, Linn.— W. E. de W.] 
Jaculus jaculus, Linn. (Plate LIII.) 
Mm csgyptius, Sic./’ Hasselq. Act. Soc. II. Sc. Upsal. 1750, p. 17; id. Act. Stockli. 1752, p. 123, 
t. 4. fig. 1. 
Mus jaculus, Linn. Syst. Nat. x. 1758, p. 63. 
Dipus hirtipes, Licht. Verz. Doubl. 1823, p. 5; id. Abh. k. Akad. Wissensch. Berk 1825 (1828), 
p. 152, tab. iv.; id. Darst. 1827, tab. xxiv. fig. sup. 
Dipus {Haltomys) hirtipes, Brandt, Bull. Acad. St. Petersb. 1844, p. 215. 
The snout is not quite so truncated as in the large species and the cheeks are less 
prominent. The ears are proportionately much shorter, since when laid forwards 
they only pass beyond the anterior angle of the eye by 2 or 3 mm., or even less; 
they are also somewhat narrower, and the posterior border above is more rounded. 
The ears are finely clad with hairs internally, and along the anterior border there is a 
fringe of long hairs gradually becoming shorter towards the upper margin, where they 
are not more than 1 mm. long. The backs of the ears appear nude to the naked 
eye, but they are in reality very sparsely covered with minute hairs. The thumb is 
minute, but furnished with a fiat nail. The claws of the other fingers are long, curved, 
and sharp. Tiiere is a large palmar tubercle immediately behind and external to the 
thumb, with another but smaller tubercle external to it, the portion of the palm imme¬ 
diately before them being swollen. There are long hairs immediately behind these 
tubercles, and the upper surfaces of the toes are finely clad with long, outwardly curved, 
white hairs. The palm itself is perfectly nude, but on the sides of the fingers there are 
a few white hairs curving inwards. The'three toes of the hind foot are more laterally 
compressed than in the other species, and this is especially observable in the cushions 
below the nails. The claw of the middle toe is feebler, and only about half the length 
of that of the inner toe, which, with the outer, is broad, bare, flat externally, and 
