The markings are subject to a good deal of variation as well as the ground colour. The usual wavy or zigzag line down the centre of the back, with a series of spots on either side, may be broken up into oval spots; and the characteristic pair of dark bars on the head may form either a */\* or an *X*. The broad shields which cover the lower surface may be grey, brown, bluish, or black, or bluish with triangular spots of black, sometimes with white dots along the margins. Below the end of the tail the colour is yellow or orange. Specimens have been recorded almost entirely of a rich black, the excepted portion being the whitish underside of the head and throat. The usual haunts of the Viper are sandy heaths, dry moors, the sunny slopes of hills and hedgebanks, bramble clumps, nettle beds, heaps of stones and sunny places in woods; but we have also found it in heathy and grassy places that were distinctly and permanently wet. For food they appear to prefer small mammals such as mice, shrews and voles, young weasels; but also take birds, lizards, slow-worms, frogs, newts, and large slugs. The young subsist for a time on insects and worms. The Viper retires in autumn to a hollow under dry moss among the heather, under faggot stacks or into the discarded and leaf-covered ground nests of birds. They reappear about April, and may then be seen coiled on a sunny bank, apparently more concerned to absorb heat than to find food. They pair at this season, and the young (varying from five to twenty) are born in August or September. In this species, again, the eggs are retained until fully developed, and when the young see the light they are coiled up tightly in a thin, transparent membrane, which usually breaks during the process of birth. They measure from six to eight inches, and are at once independent. The hoary old legend about the mother Viper opening her jaws to afford sanctuary to her young in time of danger has probably arisen from some occasional acts of cannibalism. It presupposes what is not true of any of our reptiles--that the young remain with their parent. They all begin life equipped for independence, and act accordingly.