43 
EXTRACTS FROM THE FOREIGN PERIODICALS. 
Zoology. 
1. On the genera Dipus and Gerbillus, —A paper was read before the 
Acad^mie des Sciences of Paris on the 29th of August, 188G, on the above in¬ 
teresting and hitherto somewhat obscure genera, by M. F. Cuvier, v/ho has 
long turned his particular attention to the Rodentia. The Jerboas (Dipus) are 
remarkable for the length of the posterior extremities, by the three toes on the 
feet, which alone touch the ground, either in jumping or walking, and which are 
only articulated to one metatarsal bone,—by a large head, a short muzzle, large 
eyes, a long tail, &c. These animals are, however, divided into several sections, 
according to the absence or the number of the rudimentary toes on the hind feet. 
M. Lichtenstein ranges them in three divisions:—1. those with three toes, nor¬ 
mally situated on the hind legs; 2, those having,in addition, another rudimentary 
toe ; 3, those with two rudimentary toes. The inspection of the heads of several 
species of the first division, says F. Cuvier, has convinced him, that these ani¬ 
mals are not only distinguished from those which have five toes.on the hind feet 
. by the number of toes, but also by the form of the molar teeth, and by the 
structure of the head. Thus while in these, the molars are numerously and irre¬ 
gularly indented, in the others there is but one indentation on each side of those 
teeth; and other differences, characteristic of the divisions, might be named.— 
The species with three posterior toes, are remarkable for the size of the head, a 
peculiarity resulting from the unusual development of various parts mentioned 
by M. Cuvier. In the kinds with five toes, on the contrary, the head is con¬ 
siderably smaller, all the parts of the ears lying in a small compass, and those 
forming the zygomatic arch being linear, thus presenting narrow surfaces for the 
insertion of the various muscles. From these observations, M. Cuvier determined 
that the Jerboas with three toes ought to be separated from those having five ; the 
former he proposes leaving in Dipus, and removes the latter to Allactaga. —M. 
Cuvier remarks, that the Gerbils (Gerbillus) have no connexion with the Jer¬ 
boas, but that they approach nearer to the Dormouse and the Rat. The memoir 
concludes with an account of a new species, Allactaga arundinis^ which appears 
to have been known to Shaw, but which has never been well described. The 
paper was accompanied by numerous figures, one representing Burton’s Gerbil; 
and nine known species were ascertained to belong to the genus. 
2. Observations on a species op Fox, inhabiting the Desert of Sahara. 
—M. Bodichon placed before the Academic some details relative to an animal 
having the appearance and habits of a Dog, but which he believes to appertain to 
the genus Fox, Vulpes. We present Mons. B.’s remarks without comment:— 
The cranium is flattened above; the head is long; the ears are high in 
the head, as in the Jackal, and long; neck slender and lengthened; the 
