1871.] speke's antelope and allied tragelaphi. 483 



description of their hiding in the water, and inability to run on hard 

 ground are entirely from native accounts." 



Mr. Oswell has also most kindly, and I fear at considerable in- 

 convenience, forwarded me for comparison the specimen brought 

 by him from Lake N'gami. 



The Nakong is mentioned by Mr. Baines in his ' Explorations in 

 S.W. Africa' (p. 458), also by Mr. Andersson in his ' Lake N'gami' 

 (p. 449). The latter brought home a damaged skin, and a sketch 

 of the head, which he submitted to Dr. Gray for identification ; but 

 that gentleman naturally, owing to the meagre materials at that 

 time at his command, expressed himself " unable to determine its 

 exact nature, but seemed inclined to consider it identical with Tra- 

 yelaphus euryceros" (see 'Lake N'gami,' p. 449). 



Being very desirous to arrive at some definite conclusion concerning 

 this Antelope and the two species of Tragelaphus, viz. T. euryceros 

 and T. angasii, with which, I have reason to believe, it has been 

 occasionally confounded, I have lately made a very careful exami- 

 nation and comparison of all the heads and skins belonging to these 

 three species that I could get access to, both in the British Museum 

 and elsewhere ; and I must express my obligation to Dr. Gray for the 

 courtesy with which he has afforded me every facility for examining 

 the specimens under his care, and to Mr. Gerrard for the very great 

 patience with which he has assisted me in that examination. 



I will now describe the characters by which I believe the skulls 

 and horns, the materials most commonly presented to our judgment 

 in the case of the rarer Antelopes, may be, in case of the three species 

 under consideration, at all times distinguished from each other. 

 For the full description of T. spekii, see P. Z. S. 1864, p. 103 ; for 

 that of T. angasii, P. Z. S. 1848, p. 89 ; and for that of T. eury- 

 ceros, Proc. Soc. Nat. Hist. Bost. 1852, p. 299. 



In the accompanying drawings, figs. 1 and 2 (pp. 486, 487) re- 

 present heads in my own collection, which specimens I have the 

 pleasure of submitting for examination this evening. Fig. 3 (p. 488) 

 is taken from the type specimen of T. euryceros in the British Mu- 

 seum, the skulls having unfortunately been destroyed in the case of 

 my own specimens of this Antelope. 



It will be seen that there is a most remarkable difference in size 

 between these three Antelopes, T. euryceros being, roughly speak- 

 ing, as much larger than T. angasii as that species is larger than 

 T. spekii — the difference between T. euryceros and T. spekii being 

 about equal to that existing between a Wapiti and a Fallow Deer. 



The difference of mere size is so great that, had it been duly 

 observed, it would have been, I think, impossible for confusion to 

 have taken place between Antelopes differing so widely in this and 

 many other features. 



For the purpose I have in view, it is unnecessary to go into oste- 

 ological details ; but there are also, as may be observed, considerable 

 differences in the form of the skulls — the most remarkable of which 

 is, perhaps, the breadth of T. euryceros across the cheeks, a mea- 

 surement taken from the most laterally projecting parts of the 



