Aristotle says, "there are animals whose nature are ambiguous, and partake, in some measure, of the human and quadruped species; such as the pithecos, the kebes, and the cynocephali. The kebe is a pithecos with a tail; the cynocephalus is perfectly like the pithecos, but larger, stronger, and has a more pointed muzzle, approaching very near that of a bull-dog, from which it derives its name: its manners are also more ferocious, and its teeth stronger than those of the pithecos, and more resemble those of a dog." It is clear, from this passage, that neither the pithecos nor cynocephalus, mentioned by Aristotle, have any tail; for he says, that the pithecos with a tail, is called _kebe_; and that the cynocephalus resembles the pithecos in every particular, except the muzzle and teeth. Aristotle, therefore, speaks of two apes without tails, the pithecos and the cynocephalus; and of others with tails, which he calls _kebes_. Now, to compare what we at present know with what was known by Aristotle, we shall observe, that we have seen three species of apes without tails, namely, the orang-outang, the gibbon, and the magot, not one of which is the pithecos; for the two first were certainly unknown to Aristotle, being only found in the southern parts of Africa and India, which were not discovered till after his time: besides, they have very different characters from those he ascribes to the pithecos. But the third species, which we call the magot, or Barbary ape, is the cynocephalus of Aristotle, for it possesses all its characters; it has no tail, its muzzle is like that of a bull-dog, and its canine teeth are large and long. This animal is also found in Asia Minor, and in other provinces of the East, and with which the Greeks were well acquainted. The pithecos belongs to the same country, but we have not seen it, and know it only from the relations of travellers, and, although during twenty years, in which we have made the research of these animals our study, this species has not fallen under our inspection, yet we do not doubt but that it as really exists as the cynocephalus. Gesner and Johnston have given figures of this pithecos. M. Brisson mentions his having seen it, and he distinguishes it from the cynocephalus, which he also saw, and confirms Aristotle's remark that these two animals perfectly resemble each other in every respect, excepting the face, which is shorter in the cynocephalus than in the pithecos. We have already observed, that the orang-outang, the pithecos, the gibbon, and the magot, are the only animals to which we can apply the generic name of ape, being the only animals which have no tail, and rather choose to walk on two legs than four. The orang-outang, and the gibbon, are very different from the pithecos and the magot. But, as the two latter perfectly resemble each other, except in the length of the muzzle, and size of the canine teeth, they have been often taken for each other. They have always been mentioned by