9O NATURAL HISTORY ESSAYS 



evidence than so variable a character as colora- 

 tion. For example, the horns of young adult 

 individuals frequently exhibit distinct annula- 

 tions near the bases, these rings being more 

 distinct behind than in front, and tending to 

 disappear with advancing age. A photo-engraving 

 has been published, which represents a pair of 

 these antelopes still living in the Antwerp Zoo- 

 logical Gardens : it was taken several years ago, 

 and the rings on the horns of both animals appear 

 quite distinctly in the picture. I have since several 

 times examined these individuals (in 1900 and 

 1902) : the horns of the bull are now only faintly 

 annulated, those of the cow, however, still retain 

 five rings on each horn, most distinctly marked 

 behind. These more or less evanescent ornaments 

 are analogous to the persistent annulations seen on 

 the horns of the various hartebeests, and are a 

 further indication that both hartebeests and wilde- 

 beests are sprung from the same ancestral stock. 

 The blue wildebeest is specially interesting to 

 naturalists, as it is probably identical with the 

 mysterious creature known to the ancients as 

 the Katoblepas (*O/?A^) which was said to inhabit 

 Ethiopia, near the sources of the Nile. Pliny 

 says that the katoblepas was savage, but sluggish, 

 resembling a bull ; its head was ponderous, and 

 carried low, so that its glance was directed down- 

 ward ; a flowing mane descended over the face, 



