150 Mr. O. Thomas on 



but size, as ganged by skull, averaging slightly larger. 

 Colour paler, the flanks especially paler and more hoary grey, 

 and the tail generally more or less whitened beneath in its 

 terminal half. In true hngicaudatus the tail is uniformly 

 brown throughout. 



Dimensions of no. 849 (type), measured in the flesh : — 



Head and body 158 mm. ; tail 225 ; hind foot 32 ; 

 ear 20. 



Skull : greatest length 39*2 ■; condylo-incisive length 35*4 : 

 zygomatic breadth 18*4 ; nasals 15; interorbital breadth 5'6 ; 

 palatal foramina 7*5 ; upper molar series 6*5. 



Localities. Medje, Upper Ituri (type) ; Pilipili (Makala), 

 Ituri ; Fundi, Ituri ; and Poko, Upper Welle. Twelve 

 specimens examined. 



GRAMMOMYS, gen, nov. 



Like ThamnomySj but the postero-internal or u x" cusp of 

 the first and second molars reduced to a mere connecting- 

 ridge running from the inner cusp of the median lamina to 

 the hinder point of the tooth. 



External characters as in Thamnomys. 



Type. Grammomys dolichurus (Mus dolichurus, Smuts). 



When originally founding the genus Thamnomys, I pointed 

 out that it contained two groups of species: (1) the typical 

 Thamnomys, with the cusp x strongly developed, and 

 (2) those more or less intermediate between Thamnomys and 

 Epimys, in which this cusp was reduced to a narrow ridge, 

 often hardly perceptible. 



With the great increase in the number of known species, I 

 now think it advisable that this intermediate group should 

 have a special name. 



To Thamnomys proper there only belong the following 

 forms: — venustus (type), rutilans, kuru, and kempi ; while 

 there go into Grammomys the great mass of the known 

 species, including dolichurus, surda.ster, ruddi, baliolus, bun- 

 tingi, ibeanus, macmillnai, cometes, d scolor, gigas. dryas, and 

 a few others described as subspecies of these. 



Deomys christyi, sp. n, 



Size about the same as in D.ferrugineus^ General colour 

 above paler and more drabby ; the ground-colour along the 



he naturally considered the name lonyicaudatus given by Tullberg as ante- 

 dated by Bennett's Mus hngicaudatus from S. America. But now that 

 these rats are no longer placed in Mus, Tullberg's name, given in con- 

 junction with the incorrect generic term Dasymys, becomes again avail- 

 able for the Cameroons form. 



