40 



SCIENTIFIC KESULTS FROM THE MAMMAL SURVEY. 



No. XV. 

 (A) The Indian Gerbils or Antelope Rats. 

 By R. C. AVroughton. 



The group of animals represented by the name Gerbilhs 

 wcZicws, m Blanford's Mammalia (No. 2C4), was recognised as a 

 sub-genus of Gerhillus, by Lataste, in 1882 (Le Natnraliste, ii. 

 No. IG, p. 126) under the name Tatera. In 1902 it was accepted 

 as a full Genus, whose members were found from Cape Town, 

 northwards throughout Africa, and thence eastwards through 

 Persia and India to Ceylon. The tj-pe species of the genus w^as 

 " Gerhillus inclictis, Hardwicke." 



The tail in all the African species (except in nigricmida, 

 from British East Africa, which has a wholly black tail) is dark 

 above and pale below, whereas in all the Asiatic forms the tail is 

 dark above and below, and pale on the sides. Mr. W. R. Sherrin 

 has recently called my attention to a skull character, viz., the 

 shape of the parietal bone, which on examination proves to be 

 quite as constant a distinguishing character as the tail pattern. I 

 now therefore have no hesitation in separating the African forms 

 as a distinct Genus, which I propose to call. 



Taterona, gen. nov. 



Genotype Taterona afra (Gerhillus afer, Gray.) 



The tail is dark above and pale i3elow (except in nigricauda, 

 where it is entirely black), whereas in restricted Tatera, it is dark 

 above and below and pale at the sides. 



The lateral sutures of the parietal, from the post-orbital pro- 

 cess backwards, run horizontally for a certain distance, then turn 

 vertically downwards for a greater or less distance; and again 

 return sharply to the horizontal. In Taterona the length of the 

 middle vertical part of the suture varies a little, but never ex- 

 ceeds one-third of the distance between the post-orbital process 

 and the downward turn, while in 'Tatera it is approximately equal 

 to this distance. 



In Taierona the basi-sphenoid appears to taper forward to a 

 point or narrow neck, owing apparentljj to the turning upwards 

 of the lateral edges, almost to the vertical ; in Tatera, in which 

 these edges are less turned upwards the basi-sphenoid does not 

 seem to taper. 



Finally in Taterona the bridge over the ante-orbital foramen 

 is relatively wider than in Tatera and the plate below the 

 lachrymal formed by the flattening of the front edge of the orbit 



