071 the East- African Representative of the Bongo. 309 



XLIV. — On the East-African Representative of the Bongo 

 and its Generic Position. By Oldfield Thomas, F.R.S. 



For some years the presence of a large Tragelaphlne antelope 

 in the district of the Ravine Station, British East Africa, has 

 been recorded, and guesses made as to its identity with species 

 known elsewhere. In 1897 Mr. F. J. Jackson seat home a 

 pair of horns, with certain native information about them 

 which now proves to be remarkably correct ; and these horns 

 were figured by Mr. Sclater in the ' Proceedings of the 

 Zoological Society ' *, with the suggestion that they might be 

 the horns of T. Angasi. 



Now at last the mystery is cleared up by Mr. F. W. Isaac, 

 who has obtained through the natives, and presented to the 

 National Museum, a remarkably fine series of this antelope, 

 which proves to be not the Inyala, but a close ally of the 

 Bongo, hitherto only recorded from West Africa. 



The most noteworthy point about Mr. Isaac's series is the 

 definite proof they give that this animal, belonging to a group 

 with the females normally hornless, has long horns in that 

 sex — a character fully of generic importance. Gray's distinc- 

 tion of the genus '^ Euri/ceros^^ f, supported alone of recent 

 writers by Dr. Jentink, therefore proves to have been correct. 

 But the name Euryceros, being preoccupied J, will require to 

 be changed, and I would suggest that of Boocercus, based on 

 the characteristic bovine tail of B. eurycerus. 



No evidence as yet exists as to whether the true western 

 Bongo has horns in the female, no examples of that sex, 

 horned or hornless, being in any European museum. But 

 should it prove, contrary to all probability, that there are no 

 horns in the West-African females, I would expressly assign 

 as the type of the genus Boocercus the East-African form 

 which we know to possess them. 



This East-African form, so far as there is western material 

 for comparison with Mr. Isaac's fine set, appears to be very 

 closely allied to tiie true Bongo, but may be subspecifically 

 distinguished as follows : — 



Boocercus eurycerus Isaaci, subsp. n. 



Closely similar to the true B. eurycerus. Size very large ; 

 skull of male considerably larger and heavier than that of the 

 type form (see measurements below), strongly convex above, 



* P. Z. S. 1897, p. 455. 

 t P. Z. S. 1850, p. 144. 

 X Lesson, Cent. Zool. p. 217 (1830). 



