SALAMANDER. Salamanders in the restricted sense (genus Salarnandra) are allies of the newts, but of exclusively ter restrial habits, indicated by the less compressed tail. The genus is restricted to the western parts of the Palaearctic region and represented by four species: the spotted salamander, S. maculosa, the well-known black and yellow creature inhabiting central and south Europe, north-west Africa, and south-west Asia ; the black salamander, S. atra, restricted to the Alps; S. caucasica from the Caucasus, and S. luschani from Asia Minor. Salamanders, far from being able to withstand the action of fire, as was believed by the ancients, are only found in damp places. They often emerge in great numbers in misty weather or after thunderstorms. Although harmless to man, the large glands on their smooth, shiny bodies secrete a milky poison, which protects them from many enemies. The bright coloration of S. maculosa is therefore probably of warning function.
The two well-known European species pair on land, the male clasping the female at the arms, and the impregnation is internal. Long after pairing the female gives birth to living young. S. macu losa, which lives at low altitudes (up to 3,000ft.), deposits her young, 10 to 5o in number, in the water, in springs or cool rivu lets, and these young at birth are similar to small newt larvae, and provided with external gills. S. atra, on the other hand, in habits more hilly regions, up to 9,000ft. Such altitudes not being,
as a rule, suitable for larval life in the water, the young are re tained in the uterus until after metamorphosis. Only two young, rarely three or four, are born, and may measure as much as somm. at birth, the mother measuring only 120. The fertilized eggs are large and numerous, as in S. maculosa, but only one develops in each uterus, the embryo being nourished on the other eggs, the embryos of which break down into a soupy "vitelline mass." The embryo passes through three stages—(I) still enclosed within the egg membrane and living on its own yolk; (2) free, within the vitelline mass, which is swallowed by the mouth; (3) there is no more vitelline mass, but the embryo develops long external gills, which serve for a nutritive exchange through the maternal uterus, these gills functioning in the same way as the chorionic villi of the mammalian embryo's placenta. Embryos, in the second stage, if artificially released from the uterus, are able to live in water, but the uterine gills soon wither and are shed and are replaced by other gills similar to those in the larva of S. maculosa. Con versely, if S. maculosa is forced to breed without access to water, the development of the embryos becomes closely similar to that of S. atra. (See AMPHIBIA.)