226 Ih: G. Dollinan on 



ciV. p. 305). The English skull is, however, broader than 

 the Belgian one, their respective transverse diameters being 

 182 and 178'5 mm. As the latter is adult and the former 

 immature, the English skull might eventually have some- 

 what exceeded the Belgian in length. Be this as it may, I 

 am informed by the Director of the Tervueren Museum that 

 the mounted skin of the specimen to which the skull pertained 

 is 4 feet 8| inches (145"5 cm.) in height, or j)ractically the same 

 as specimens in which the skull-length is only 339 mm. 



Although, as mentioned above, no decisive evidence of this 

 is afforded by the two English mounted specimens, hornless 

 okapies are regarded as females. On the other hand, all the 

 horned examples that have como under my notice are un- 

 doubtedly males ; and since the Ituri natives affirm that the 

 bulls are armed while the cows are defenceless, the existence 

 of this secondary sexual difference may be at least provi- 

 sionally accepted. 



Assuming, then, the hornless specimens"to be truly females, 

 the foregoing data indicate that female okapies are larger 

 than males. The alternative would appear to be that there 

 is a larger and a smaller form ; but this I hesitate to admit, 

 more especially as I have not seen either an adult male 

 agreeing in stature with the females or an adult female 

 corresponding in size to the males, the smaller of the 

 two hornless skulls presented to the British Museum by 

 Sir H. Johnston indicating a comparatively young animal. 



XXV. — Ttoo new African Mammals. 

 By Guy Dollman. 



(Published by permission of the Trustees of the British Museum.) 



Prionomys, gen. nov. [Muridce). 



Size similar to that of a large species of Dendromns. Fore 

 feet with four well-formed digits; pollex suppressed. Digits 

 II.-IV. moderately elongated, with short claws ; outer or 

 V. digit only about half the length of the two middle fingers, 

 with a small inconspicuous nail. Hind feet with five digits, 

 all provided with claws. Hallux stout, about half the length 

 of the middle toe ; claw on hallux smaller and blunter than 



