Sioamp-Rats of East Africa. 155 



DImensionf? of the type (measured in the flesh) : — 



Head and body 150 mm. ; tail 81; hind foot 2G ; 

 ear 23. 



Skull : greatest length 37*8 ; basilar lenoth 30 ; condylo- 

 incisive length 35'4 ; zygomatic breadth 19*5; iiitcrorbit!il 

 constiiction 4'4 ; length o£ nasals 16*8 ; greatest breadth 

 across expanded part of nasals 6*5 ; depth from highest ])oiiit 

 of orbit to alveolar border at front of m^ 13*3 ; length of 

 palatal foramina 6'9 ; postpalatal lengtli 13'6; length of 

 upper molar series from anterior alveolar border to back of 

 last molar 9'5 ; lengtli from anterior base of enamel on m^ to 

 back of m^ S'G ; greatest width of m^ 2'3. 



ffab. Lake Olbollossat, Naivasha Province, British East 

 Africa. 



Ti/j^e. Adult female. B.M. no. 12. 7. 1. 431. Original 

 number 79. Collected and presented by A. Blayney Percival, 

 Esq, 



This Oiomt/s is evidently quite closely allied to the Molo 

 species; the difference in size and niuclj ])aler colour are. the 

 ciiief distinguishing characteis. Tliat a race of the Molo 

 species should occur at Olbollossat is not surprising when 

 the geographical conditions are considered. 



Mr. Percival collected two further specimens of this 

 Otomys at the type-locality ; the dimensions are given as : 

 head and body 150, 143 nim. ; tail 86, 82 ; hind foot 26, 26. 

 The skulls botii show the same curious arched formation, the 

 interorbital region being considerably elevated and the nasals 

 and cranial outline depressed. 



(5) Otomys thomasi squahis, subsp. n. 



Size rather larger than in the foregoing race, colour con- 

 siderably darker and richer. 



Size of body greater than in t. malleus, but markedly less 

 than in thomasi. General colour of dorsal surface a rich 

 brownish buff, the effect much darker and browner than in 

 malleus. Flanks not conspicuously lighter than back. Sides 

 of face and head similar in colour to back, without any 

 prominent light areas behind the ears. Backs of hands and 

 feet white, washed with pale buff. Underparts of body rather 

 darker throughout. Tail as in the other members of this 

 group. 



Skull a trifle larger than that of vialleus, with broader 

 nasals and lojiger palatal foramimi. Cranial dimensions 

 considerably less than in thomasi. 



