JACULUS OEIEXTALIS. 
307 
Measurements. 
Beltim. 
^- 
‘A 
Pyramids. 
$• 
$. 
c? (figured). 
mm. 
nira. 
mm. 
Snout to vent. 
.... 105 
105 
Ill 
Vent to tip of tail. 
156 
175 
180 
Length of bead. 
. . . . 35 
35 
34 
Height of ear. 
. . . . 16-5 
18 
18 
Breadth of ear. 
. . . . 13 
13 
15 
Length of hind foot, without claw ... 59 
55 
59 
Snout to eye. 
. . . 
21 
Eve to ear. 
11 
Diameter of eye (longitudinal) . 
* 
* . . 
10 
,, „ (vertical) 
• • • 
9 
Posterior moustachial bristle 
• • « « • t • 
» . • 
99 
Weight. 
. . • 
2 oz. 12 grs. 
Measurements of skull:—Greatest length 34 mm.; greatest breadth of anteorbital 
malar processes 24*5 ; breadth outside auditory meatus 23 ; length of nasals 13 ; heigJit 
of infraorbital foramen 7, breadth of infraorbital foramen 4’5; basal length 28 ; 
length of incisive foramina 4; length of molar series 5. 
This species probably occurs in suitable localities in the Nile Valley as far south as 
Shendi. However, specimens from different districts are needed to work out the 
ranges of the several species satisfactorily. 
Jaculus oeientalis, Erxleb. (Plate LIV.) 
Jaculus 07-ientalis, Erxleben, Syst. Reg. Anim. 1777, p. 404. 
Dipus jaculus, Gmel. Linn. Syst. Nat. 1788, p. 157 (partim, nec Schreh.). 
“ Jerboa,” Bruce, Travels, vol. v. App. 1790, p. 121, pi. 
Dipus sagitta, Schreb. Sang. iv. 1792, p. 849 (partim, nec Mus sagitta, Pall.). 
Dipus abyssinicus, Meyer, Syst. Zool. Entdeck. Neuboll. u. Afrika, 1793, p. 8G. 
Dijms gerboa, Olivier, Nouv. Bull. Soc. Pbilom. ii. 1801, p. 121; Desm. Encycl. Meth., Mamm. 
1822, p. 316. 
“La Gerboise,” Olivier, Voy. Emp. 0th. ii. 1804, p. 42. 
Dipus bipes, Licbt. Verz. Doubl. 1823, p. 5. 
Dipus locusta, lllig. ap. Licbt. Abb. k. Akad. Wissenscb. Berl. 1825, p. 152. 
Dipus cegyptius, Licbt. Abb. k. Akad. Wissenscb. Berl. 1825 (1828), p. 151, tab. i.; id. Darst. 
1827, tab. xxii. 
Diptis {Haltomys) cegyptius, Brandt, Bull. Acad. St. Petersb. 1844, p. 215. 
The snout is rather broad and short, rapidly increasing in breadth before the eyes. 
2r2 
