Chapter XXVIII.

Among serpents the viper is externally viviparous, but first of all internally oviparous. The ovum, like that of fish, is of one colour and soft skinned. The young are produced in the upper part. They are not enclosed in a shelly covering, neither are the ova of fish. The little vipers are produced in a membrane, which they rupture on the third day, and sometimes they make their escape by eating their way through the mother. They are produced one by one in the course of a day, and their number often exceeds twenty. Other serpents are externally oviparous, but their ova are joined together like women's necklaces. When the female deposits her eggs in the soil, she incubates upon them. These also are hatched in the second year. This is the manner of the production of serpents, insects, and of oviparous quadrupeds.