referred to the Genus Meriones, 265 
the small-bulla species with almost no black on the tail, later 
obtained by Dr. Anderson near Alexandria. 
This case of melanurus is a striking example of the advisa- 
bility of selecting types, a plan still resisted by naturalists of 
backward tendencies. Riippell was little to blame for mixing 
up the two species, which are really very similar to each 
other ; but had he selected an individual type to represent 
his name, all the confusion that has surrounded it would have 
been avoided. 
In the Sudan there occurs the gerbil to which Bonhote has 
applied the name M. crassus pallidus, a form belonging to 
the @ group, and undoubtedly very nearly allied to the true 
crassus of Sinai, but widely different from Lower Egyptian 
forms to which that name has been applied. 
Further eastwards material does not exist for any general 
review, but a number of local forms have proved to need 
description. It may, however, be noted that the Meriones of 
Asia Minor and Palestine seem to be mostly of the d group, 
while the remarkable MW. calurus of Egypt and Sinai has the 
bullae of the size found in group c, though the suprameatal 
triangle is unusually small. 
With regard to the aberrant MW. hurriane of Baluchistan 
and N.W. India, I find that instead of being distinctly a 
desert animal, with light skull, large bullee, and short normal 
claws, it is modified for a burrowing life by having a heavy 
bowed skull, small bullee, and elongated digging fore-claws. 
It appears to me, therefore, that it ought to be generically 
separated from the other members of the group, and I would 
propose for it the name of Che/iones*. 
Meriones pallidus tripolius, subsp. n. 
Group a. Like Sudan pall/dus in all essential particulars, 
but the general colour slightly warmer, often approaching 
cinnamon-buff, and usually getting a little darker towards 
the base of the tail. Under suriace usually white to the 
bases of the hairs, but sometimes they are pale slaty basally 
White ear-patches larger and more conspicuous, generally too 
large to be hidden by the ear when this is folded backwards, 
Tail-tuft short and little developed, its hairs scarcely exceeding 
10 mm. ; the main part of the tail pinkish buff or cinnamon- 
buff, and equally buffy below ; in pallidus it is markedly 
lighter, often white, below. 
Skull as in pallidus. 
* Derived from y#\y, exactly as Mertones is from pnpés. 
