494 Mr. R. C. VVrouglitou on 



The hind foot is given as 36-40 mm., whicli differentiates it 

 at once from the Upper Shire and Nyasa forms, wliieh have 

 a very short liind foot; it is quite possible that mombascB, 

 which also is a coast form, may be allied to leucorf aster, but 

 as, in any case, it would be worthy of sul)specihe rank, I 

 liave not hesitated to give it a distinctive name. 



(25) Tatera gracilis. 



Gerbillus gracilis, Thos. Ann. & Mag. Nat. Hist. ix. p. 77 (1892). 



85. 2. 2. 1. Gambia {Sir C. A. Moloney). (Type in al.) 

 I quote the dimensions recorded by Mr. Thomas : — 

 Head and body 92 mm.; tail 131; hind foot 29; ear 15-5. 

 Skull: greatest length 32 ; (basilar length 23;) zygomatic 

 breadth 15-7 ; length of upper molar series 5'1 ; bullae 10, 

 This is the smallest species of the genus known so far. 



(26) Tatera robusta. 



Meriones rohustu-^, Cretzsch. Atlas Reis. N. Afr. C1826). 

 Meriones muritius^ Sundevall, "Vet.-Ak. Handl. (1^42). 



1. 5. 5. 34-39. Shcndy, Nile Valley (^Rothschild). 



4. 11. 3. 59-63. Naikhaia, Upper Egypt {Rothschild). 



5. 5. 8. 24-30. Khartoum, Upper Egypt {Butler). 



3.2.7. 18-20. El Kowa, Soudan {Mrs. Anderson). 



0. 3. 3. 23. Roseires, Blue Nile {Lord Lovat). 



Cretzschmar's description is very vague, and there is 

 little beyond the locality to guide to an identification ; this 

 is given as " Kordofan.'^ The tyi)e was collected by Riippell, 

 who, in his Catalogue of the Mammalia, gives its habitat as 

 " Nubien " ; finally, Mr. Thomas, wlio has seen the specimen, 

 informs me that it is labelled ''Ambukol, Nubien." Sun- 

 devall's description of murinus, though long and detailed, 

 furnishes practically little on which to distinguish his species 

 from robusta. He himself says: — "A. robusto, Riipp., 

 differt auriculis non acutis et rostro multo produotiore sed 

 mensurse fere esedem videntur.'^ The differences, it will be 

 noted, are such that they may be due as much to the taxi- 

 dermist as to natural selection. With the exception of the 

 single specimen from Roseires all the Museum specimens are 

 practically from the Nile banks between 13° and 17°. Un- 

 fortunately the specimens from Shendy, the nearest point to 

 the type-locality from which we have specimens^ are all 

 young. Amongst them is one skull (1.5.5.37) markedly 

 larger in every way than the rest, and, indeed, than almost 

 anv other skull in the collection from the Nile Vallev, but 



