One of the most famous amongst these fabulous animals of the ancients, is the _unicorn_. Even to our own time people have obstinately persisted in searching for it, or, at least, in seeking arguments to prove its existence. Three separate animals are frequently mentioned by the ancients as having only one horn in the middle of the forehead. The _African oryx_, having cloven hoofs, the hair placed in the contrary direction to that of other animals[69], equal in size to the bull[70] or even the rhinoceros[71], and said to resemble deer and goats in form[72]; the _Indian ass_, having solid hoofs; and the _monoceros_, properly so called, whose feet are sometimes compared to those of the lion[73], and sometimes to those of the elephant[74], and which is therefore considered as having divided feet. The one-horned horse[75] and one-horned bull are doubtless both to be referred to the Indian ass, for even the latter is described as having solid hoofs[76]. I would ask, If these animals exist as distinct species, should we not at least have their horns in our collections? And what single horns do we possess, excepting those of the rhinoceros and narwal? How is it possible, after this, to refer to rude figures traced by savages upon rocks[77]? Ignorant of perspective, and wishing to represent a straight horned antelope in profile, they could only give it a single horn, and thus they produced an oryx. The oryxes, too, that are seen on the Egyptian monuments, are probably nothing more than productions of the stiff style, imposed upon the artists of that country by their religion. Many of their profiles of quadrupeds shew only one fore and one hind leg; and this being the case, why should they have shewn two horns? It may perhaps have chanced that individuals have been taken in the chace, which had accidentally lost one of their horns, as pretty frequently happens to the chamois and saiga: and this would have been sufficient to confirm the error produced by these representations. It is probably in this way that the unicorn has recently been reported to be found in the mountains of Thibet. All the ancients, however, have not represented the oryx as having only one horn. Oppian expressly gives it several[78], and Ælian mentions oryxes which had four[79]. Finally, if this animal was ruminant and cloven-hoofed, we know assuredly that its frontal bone must have been longitudinally divided into two, and that it could not, as is very justly remarked by Camper, have had a horn placed upon the suture.