220 
Back of hams white, the white not projecting into the dark body-colour. 
Tail long, well-haired, but not crested, blackish above and below, except just 
at its base. 
Skull-dimensions in an adult male:—Basal length 7:5 inches, greatest 
breadth 3:7, muzzle to orbit 4:2. 
Horns attaining about 11 or 12 inches in length; their basal halves 
broadly ringed, their long forwardly-directed terminal halves smooth and 
evidently corresponding to the short smooth recurved tips of ordinary 
Gazelline horns. 
Female. Similar to the male, but without horns. 
Hab. Eastern parts of Central Somaliland, restricted to the Dolbahanta 
and Marehan countries S.E. of Berbera. 
We now conclude the long series of Gazelles with three abnormal forms, 
each constituting a genus of itself, which, curiously enough, are all restricted 
to N.E, Africa. As regards the first two of them there can be no question, 
we believe, of their close alliance to the Gazelles, Ammodorcas being, in 
several respects, intermediate between Gazellla and Lithocranius, and leading 
on to that most specialized form of the group. About the correct position 
of the Beira, however, there is considerable doubt, and it is quite possible 
that a more natural place for it in the Antelopine series may be hereafter 
discovered. 
The Dibatag, or Clarke’s Gazelle, was first met with by the sportsman and 
naturalist whose name it bears in 1890, during his exploring trip into the 
Dolbahanta and Marehan country south-east of Berbera. Writing to Thomas 
about his discovery, Mr.'T. W. H. Clarke (of Secheron, Battery Point, Hobart, 
Tasmania) says (see P.Z.S. 1891, p. 209) :-— 
“T saw this Gazelle for the first time on December i7th, 1890, about three hours 
from ‘ Bairwell, or about one day from ‘ Buroa Well, Habergerhagi’s country, and 
afterwards on the road all the way into the Marehan district, 8° N., 47° E. I killed a 
male, and found one of the horns broken off close to the skull, which had apparently 
been done a year or so ago. 
«They are very graceful animals, with a long neck and well-proportioned head and 
horns; the body is rather slender, but considerably larger than in Gazella spekei, about 
the size of a female G.walleri. The legs are long and slender ; the hoofs are not so 
triangular as those of G. spekei, and small for the size of the animal. They have small ears 
