9. The human bladder is moderately large in size, and the pudendum is united to the neck of the bladder, having a strong passage above and a small one below. One of these passages leads to the testicles; the other, which is sinewy and cartilaginous, to the bladder. From this are appended the testicles of the male, concerning which we will treat in the part devoted to their consideration. These parts are the same in the female, who differs in none of the internal parts except the womb, the appearance of which may be learned from the drawings in the books on anatomy. Its position is upon the entrails. The bladder is above the uterus. In a future book we will speak of the nature of the uterus generally; for it is not alike, nor has it the same nature in them all. These are the internal and external parts of the human body, and this is their nature and their manner. BOOK THE SECOND. CHAPTER I. 1. Of the parts of other animals some are common to them all, as I have said before, and some belong to particular classes, and they agree and differ in the manner often before mentioned. For almost all animals which differ in kind, have also their parts different in form, and there are some which have only a proportionate resemblance, but differ in kind, and others agree in kind, but not in form, and many parts belong to some which others have not. Viviparous quadrupeds have a head and neck, and all the parts of the head, but they differ from each other in their forms. The lion has one bone in the neck, but has no vertebræ, and when laid open its internal parts are like those of a dog. 2. Viviparous quadrupeds have fore-legs instead of arms, and in all quadrupeds, especially those which have the fore-feet much divided, they are analogous to hands, for they use them as hands, and the left legs are less at liberty than in men, except in the elephant, and this animal has the toes less perfectly jointed, and its fore-legs much larger than the hind ones; it has five toes, and short ankles to its hind legs. It has a trunk of such a nature and length as to be able to use it for a hand, and it drinks and eats by stretching this into its mouth; this also it lifts up to its driver, and pulls up trees with it; with this organ it breathes as it walks through the water. The extremity of the proboscis is curved, but without joints, for it is cartilaginous. 3. Man is the only ambidextrous animal. All animals have their chest analogous to man, but not similar to his, for he has a wide chest, and theirs is narrow: no animal but man has pectoral mammæ; the elephant has two mammæ, but not on the breast, though they are in that direction.