KUNGL. SV. VET. AKADEMIENS HANDLINGAE. BAND 48. N:0 5. 155 



Rhynchotragus guentheri wroughtoni Drake-Bbookman, 



Dkake-Bkockman: Ann. & Mag. Nat. Hist., Ser. 8. Vol. IV, p. 51. 



When the expedition had crossed Guaso Nyiri to tho northern side at the ford 

 on the Marsabit road Dik-diks were found to be rather common in the thornbush. 

 On the first and second days march towards the east from the ford mentioned I 

 shot five specimens of a greyish looking Dik-dik with very short nasals and a well 

 developed proboscis (PI. XIV, fig. 1), evidently belonging to the Rhynchotragus 

 guentheri group. This group which is characterised by the »tips of nasals about level 

 with the back of the middle premolar* includes Rh. guentheri Thomas with the sub- 

 species Rh. g. smithi Thomas and Rh. g. wroughtoni Drake-Brockman, and Rh. naso- 

 guttatus LoNNBERG. My specimens from the northern side of Guaso Nyiri appear to 

 differ rather strongly from all these, among other characteristics by their extremely 

 short nasals which do not attain a maximum length of more than about 10 mm., 

 and often less. The premaxillaries are very short and do not reach more than about 

 half way to the nasals. In Rh. guentheri, as Thomas kindly has written to me, there 

 is a small discontinuous remnant of the nasal process of the premaxillary left which 

 reaches the nasal suture, but nothing like this can be seen in my specimens. The 

 maxillaries again extend upwards in front of the lacrymale in the shape of a 4 to 6 

 mm. broad band which forms a suture of a similar breadth with the nasals. The 

 lacrymale is thus entirely excluded from the margin of the anterior nasal opening. 

 In the fig. of the skull of Rh. guentheri in Proc, Zool. Soc, London 1894, p. 324' 

 the lacrymale excludes the maxilla'ry from the nasals and I took this for an important 

 difference, but Thomas has in a letter kindly informed me that this figure is not 

 quite correct. In reality the maxillary reaches the nasal with a short suture in Rh. 

 guentheri. The discrepancy in this respect is thus not very important, but the dif- 

 ference in length of the nasals prove completely the distinctness of my specimens 

 from Rh. guentheri. The length of these bones is in the latter species 17 — 17,5 mm., 

 but in my specimens from 8 to 10,3 mm. In addition to this there are also diffe- 

 rences in colour which will be mentioned below. 



Rh. g. smithi Thomas was described^ on a head skin and a skull from Lake 

 Stephanie. This skull resembles, according to a communication from the author quoted, 

 with regard to the shortness of the premaxillary and the broad suture between max- 

 illary and the nasal the skulls of my specimens. But Eh. g. smithi differs markedly 

 from the latter with regard to size. Although the type skull is of a male, all its di- 

 mensions are larger even than those of my biggest female skull, in spite of the fact 

 that in these animals, as is well known, the females are always larger than the males. 

 Compared with my male skulls the basicranial length of Rh. g. smithi is about 9 "/o 



1 Reproduced in Book of Antelopes, Vol. If, p. 90. 

 ^ Proc. Zool. Soc, London 1900, p. 804. 



