522 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loe 



The specimens from Juba are near topotypes of ismailiae and are 

 fully adult, showing considerable wear on the molars. None of the 

 specimens in the type series of ismailiae are fully adult, yet the reddish 

 coloration as given by Heller as characteristic appears to be the only 

 feature distinguishing this race from ugandae as known by specimens 

 from Kampala, Uganda. Color, however, appears to be extremely 

 variable since the adult specimens from Torit range from bright 

 reddish to brownish. The skulls, though, show no marked variation 

 in configuration or measurements from the type of ismailiae. Two 

 specimens from Obbo approach ugandae in the saturate coloration 

 which appears to be typical of that race. It is apparent that in this 

 group of specimens the only ones which are truly typical of ismailiae 

 are the ones from Juba. The others, at least so far as color is con- 

 cerned, are apparently mtergrades with ugandae but more referable 

 in cranial characters to ismailiae. 



At best, the material available can be distinguished only when 

 adults are compared. Immatures from Nimule and Obbo show the 

 intense reddish coloration typical of the type of ismailiae and have a 

 white belly. In ugandae, the coloration of the belly is a strong suffu- 

 sion of buff which is shown in a few specimens from Obbo. 



Mastoinys natalensis macrolepis (Sundevall) 



Figure 7,a 



Mus macrolepis Sundevall, Kongl. Svenska Vet.-Akad. Handl., Stockholm (1842), 

 p. 218, 1843. (Sennaar.) 



Specimens Examined: All in BM, from: Dueim, 1; Kamisa, 

 Dinder River, 1; Roseires, 1; El Kowa, 1; Gedaref, 1. 



Measurements: An adult female from El Kowa measures as fol- 

 lows: Length of head and body 142; length of tail 151 ; length of hind 

 foot 24; length of ear 20; total length of skull 34.3; condyloincisive 

 length 32.3; lengtli of anterior palatine foramina 7.9; crown length of 

 upper toothrow 4.9; least interorbital width 4.6; width of rostrum at 

 level of antorbital foramen 4.3; length of nasals 14.2; greatest width 

 across zygomatic arches 17.3. 



Remarks: M. n. macrolepis may be distinguished from surrounding 

 races of M. natalensis by its generally darker color and somewhat 

 larger size. It is noticeably different cranially in that the auditory 

 bullae are markedly smaller and less inflated. 



Mastomys natalensis marrensis, new subspecies 



Figure 7, a 



Type: BM No. 23.1.1.425, adult female, skin and skull, from 

 Kulme, Wadi Aribo, Darfur Province, Anglo-Egyptian Sudan. Ob- 

 tained August 28, 1921, by Lynes and Lowe, original No. 897. 



