8 ARKIV EÖR ZOOLOGI. BAND 10. N:0 12. 



capitis Thomas as a subspecies distiuct from the typical 

 P. jacksoni, although I admit that the former as a rule is 

 less dark above and more whitish on the lower side, but 

 intergrading specimens are to be found in nearest neighbour- 

 hood of Nairobi. 



It is the same difficulty connected with exact classifica- 

 tion of these specimens as well, as may be concluded from 

 the above written description of the specimens. 



Graphiiirus parviis dollmani Osgood. 

 1 $ from Donya Sabuk ^^i 1913. 



Otomys augoiiiensis elassodoii Osgood. 



A fine series of 6 J*J* and 6 $$ from Juja farm, and 

 10 c? c? ^^^ ^ ? ? i^om Donya Sabuk, young and old. 



The largest specimen, a male from Donya Sabuk has 

 the greatest length of the skull not less than 43 mm., zygo- 

 matic breadth 21,5 mm., greatest breadth across nasals 10 mm. 



Mylomys cuiiiiiiigliamei massaicus n. subsp. 



Two Råts of this interesting genus, so easily recognized 

 on the characteristic structure of the dentition, have been 

 collected at Donya Sabuk resp. Jan. 31 and Febr. 18, 1914. 



The measurements of the skull of the largest specimen 

 which is a female are as follows: 



Greatest length 37 mm. 



Condyloincisive length .... 34,2 » 



Greatest breadth 17,8 » 



Length of nasals 13,5 » 



Combined breadth of nasals . . 4,7 » 

 Least interorbital width .... 5 » 



Diastema 9 » 



Length of palatal foramina . . 8 » 



» » molar series .... 8 » 



Breadth across outside m' . . . 7,4 » 



» of m' 2,8 » 



As the sutures of the skull all of them still are open, 

 and the teeth not much worn, the specimen must not be 

 very old, although, of course, it is fully adult. Thomas 



