the Genus Otomys. 275 



Head and body 180 mm. ; tail 80; hind foot 30 j car 23. 



Skull : greatest length 44 ; basilar length 35 ; zygomatic 

 breadth TZ ; length of u[)[)cr mohir series 9 ; bulhc 7"5. 



In acUlition to the eluiraeters recorded by jMr. Thomas, a 

 subterminal compression of the nasals is most marked, and 

 with the generally narrower nasals serves to distinguish 

 tropicalis from anyoniensis at a glance. The Mianzini series 

 shows this compression of the nasals very strongly, and tlie 

 brain-case is even broader and deeper than in the specimens 

 from Mt. Kenya ; but the skins seem to belong to a much 

 smaller animal and, moreover, vary a good deal in colour. 

 No measurements, however, were recorded by the collector; 

 I therefore reluctantly place them under this species. 



(12) Otomys irroratus Denti. 



Otomys Denti, Thos. Ann. & Mag. Nat. Hist. vol. xviii. p. 142 (1906). 



6.7.1.68-70. Ruwenzori E.Kploratiou. Ait. G030- 

 10,000'. 



A rather small dark-coloured Otomys, with the tail wholly 

 black, above and below, and black feet. 



The dimensions are : — 



Head and body 165 mm. ; tail 95 ; hind foot 27 ; ear 21. 



Skull : greatest length 37 ; basilar length 30; zygomatic 

 breadth 19 ; length of upper molar series 7'5 ; bullae 7. 



The presence of only five laminae in m^ is sufficient to 

 distinguish this from any other member of the northern 

 group or, indeed, of Section II. 



Mr. Thomas has described this form as a species, but as 

 I have ranked all the other forms as subspecies of irroratus 

 I feel it more convenient to treat Denti in the same way, 

 notwithstanding the laminae formula of m". 



(13) Otomys irroratus orestes. 

 Oto7nys irroratus orestes, Thos. P. Z. S. 1900, p. 175. 



0. 2. 1. 21 . Teliki Valley, Mt. Kenya, B.E.A. {Machnder). 

 Alt. 13,000'. 



The dimensions of this species as recorded by ]\Ir. Thomas 

 are : — 



Head and body 175 mm. ; tail Q2 ; hind foot 27 ; ear 20 5. 



Skull: greatest length 39 ; basilar length 31-3 ; zygomatic 

 breadth 20; leugth of upper molar series 8; bullae 7-5. 



The smaller size, comjiaratively narrow nasals, and pre- 

 sence of only six laminae in lit" serve to distinguish it from 

 any of its neighbours. 



