CHAPTER VIII. 1. We must now treat of the Senses: for they are not alike in all, but some have all the senses, and some fewer. They are mostly five in number; seeing, hearing, smelling, taste, touch, and besides these there are none peculiar to any creatures. Man, then, and all viviparous animals with feet, besides all sanguineous and viviparous animals, have all these, unless they are undeveloped in any particular kind, as in the mole. 2. For this creature has no sight, it has no apparent eyes, but when the thick skin which surrounds the head is taken away, in the place where the eyes ought to be on the outside, are the undeveloped internal eyes, which have all the parts of true eyes, for they have both the iris of the eye, and within the iris the part called the pupil, and the white; but all these are less than in true eyes. On the outside there is no appearance of these parts, from the thickness of the skin, as if the nature of the eye had been destroyed at birth; for there are two sinewy and strong passages proceeding from the brain, where it unites with the spinal cord, reaching from the socket of the eye, and ending upon the upper sharp teeth. 3. All other animals are endued with the perception of colours, sounds, smells, and taste. All animals have the fifth sense, which is called touch. In some animals the organs of sense are very distinct, and especially the eyes, for they have a definite place, and so has the hearing. For some animals have ears, and others open perforations: so also of the sense of smelling, some animals have nostrils, others passages, as the whole class of birds. In the same way the tongue is the organ of taste. 4. In aquatic animals and those called fish, the tongue is still the organ of taste, though it is indistinct, for it is bony, and not capable of free motion. In some fish the roof of the mouth is fleshy, as in some cyprini among river fish, so that, without careful examination, it appears like a tongue. That they have the sense of taste is quite clear, for many of them delight in peculiar food, and they will more readily seize upon a bait formed of the amia and other fat fishes, as if they delighted in the taste and eating of such baits. 5. They have no evident organ of hearing and smelling, for the passages which exist about the region of the nostrils in some fish do not appear to pass to the brain, but some of them are blind, and others lead to the gills; it is evident, however, that they both hear and smell, for they escape from loud noises, such as the oars of the triremes, so as to be easily captured in their hiding-places.