Page:Natural History, Reptiles.djvu/134

126 it. Thus it will often take a great number of the smaller insects, preferring those of the dipterous order; though it will not refuse many of the coleoptera or orthoptera, if they be not too large.

"Instead of depositing her eggs in the sand to be hatched by the warmth of the sun, the female of the present species retains the eggs within the oviduct until the young are ready to leave them, and they are produced alive. As in all the ovo-viviparous reptiles, the covering of the egg is very thin, and merely membranous. In this respect they differ from those which deposit their eggs before the embryo is formed. In the latter case a more efficient protection is necessary, and the covering is either calcareous, as in the Tortoises and Crocodiles, or of a substance resembling parchment, as those of the Snakes and most Lizards. In the Viper, which also produces its young alive, the covering, as in the present animal, is extremely thin and very easily torn; and there is reason to believe that the laceration of this membrane and the emancipation of the young take place in, and are occasioned by, the very act of parturition.

"As the young ones are occasionally found with the mother, there is some reason to believe that these little animals are not wholly devoid of the instinct of parental care and tendance; but it is scarcely probable that the exercise of this feeling is ever very powerful, or that it endures for any considerable period. The young, when brought forth, are fully formed and capable of running about, and very shortly afterwards of taking their own food. The usual number is from three to six.