ABSTRACT
IN many of the lower animals the sexes are combined in every individual. We do not find male and female earthworms or male and female snails. In these forms every individual is an hermaphrodite, functioning both as male and female. Among vertebrates normal hermaphroditism is on the contrary very rare, being confined to the hag-fish (Myxine), the sea-bass (Serranus), and a very few other fishes. But among those vertebrates in which the sexes are normally separate, an individual is occasionally found with abnormal reproductive organs comprising both male and female elements. In mammals the best known example is the “free-martin” or sexually-abnormal heifer. In European breeds of pigs and goats intersexes also occur from time to time. Farmers call pigs of this type “wilgils” or “wildews”. Their anatomy has been studied in detail by Dr. Crew 1 and myself 2 among others. The gonads 3 are usually degenerate testes without sperms, but sometimes there 116is a little patch of ovarian tissue on one or both of the testes, or one of the two gonads may be an ovary. The external organs generally approximate to the female type, though the clitoris (which in the normal female is the very small representative of the penis of the male, not showing externally) is usually enlarged so as to distort the vulva (the external opening of the female system) to some extent. As regards the internal organs other than gonads, there is usually a more or less well-developed male system, as well as a more or less well-developed female system. Thus some rudiments at least can often be found of all the following organs :—
