The skin is shed periodically, and rather often by the rapidly growing young; by the adult, during the life in the water, rarely during the sojourn on dry land. The skin breaks round the mouth; assisted by the fingers and by contortions of the {124}body, it is then slipped backwards over the trunk and tail, whereupon the newt seizes the skin with the mouth, draws the shirt off entirely, and–swallows it. Such freshly shed skins are very delicate and pretty objects when suspended in water or some preserving fluid. The shed skin, consisting only of the outermost layer of the epidermis, is entire, but turned inside out, with fingers and toes complete, the only holes being those for the mouth, eyes, and vent. None of the Tritons are viviparous. The eggs, which are glued singly or in small numbers on to stones or water-plants, are hatched in about a fortnight, sooner or later according to the species and the prevailing temperature. The larvae are always provided with three pairs of branched external gills; the fore-limbs appear much earlier than the hind-limbs. Most, perhaps all, larvae develop two pairs of thread-like protuberances on the sides of the upper jaw, by means of which they attach or anchor themselves on to water-plants shortly after they are hatched. Thus moored they remain motionless in a slanting position, now and then wriggling their tails and shifting their place, or sinking to the bottom. The metamorphosis is finished during the first summer, and the little newts, often partially transparent, leave the water to hide under stones. Not unfrequently the metamorphosis is retarded and not finished by the autumn. The larvae of _T. cristatus_, especially when reared in ponds with abrupt or overhanging banks, so that they cannot leave the water, retain considerable remnants of the gills, still more frequently the clefts, although breathing chiefly by the lungs. Such individuals reach a length of 3 inches, and are larvae so far as the finny tail and the gills are concerned. They hibernate in this condition, and in exceptional cases reach sexual maturity;–at least the females, which develop ripe eggs; the males are not known to produce spermatozoa. Much has been written on the amorous games of newts, but it is only recently that the mode of fecundation has been actually observed. Gasco[60] placed the newts in glass vessels suspended from the ceiling of his laboratory. The antics of the enamoured male around the female, rubbing the latter with its head, or lashing it gently with the tail, and playing around it in its often beautiful nuptial dress, are meant to excite the {125}female. The male then at intervals emits spermatophores, which sink to the bottom, and the female takes them up into its cloaca. For further information see p. 54.