THE DIKDIKS 623 



same age, but have not been observed in other genera of 

 antelopes. 



The short nasal bones, the large anteorbital fossae and 

 the great size of the narial opening of the dikdiks ally them 

 closely to the gazelles and separate them fairly widely from 

 the other groups of small antelopes with which they are usu- 

 ally grouped. In the structure of the snout they resemble 

 closely the proboscis-bearing Saiga, which shows an even 

 greater reduction of the nasal and the premaxillary bones. 

 The skulls of newly born gazelles are scarcely distinguish- 

 able in shape of nasal bones or relative size of the narial 

 opening from those of adult dikdik. There are two genera: 

 RhynckotraguSy bearing a large proboscis, and Madoqua, 

 having the proboscis smaller and the premaxillary bones 

 normal. The latter genus is confined to Somaliland and 

 Abyssinia, and is not known to occur in British East Africa. 



Long-Snouted Dikdiks 



Rhynchotragus 



Rhynchotragus Neumann, 1905, Sitz.-Ber. Ges. Nat. Freu., Berl., p. 88; type 

 Madoqua guentheri Thomas. 



In the long-snouted dikdiks the coloration is much more 

 subdued than in Madoqua, the colors never being bright 

 orange. The body size is also larger and the proboscis is much 

 more developed, being fully twice as great in length. The 

 skull has the nasal bones more reduced and the premaxillary 

 bones widely separated from the nasals. The last lower 

 molar tooth has three folds to the crown instead of two as 

 in Madoqua. The genus ranges from central Somaliland 

 and Abyssinia southward through the coast and Rift Valley 

 drainage area to central German East Africa. It is not 

 known to occur west of the Rift Valley in the Nile drainage. 

 An isolated species, damarensis, occurs in German Southwest 

 Africa and Angola. No fossil species are known. 



