SUB-FAM. 1. DESMOGNATHINAE.–Comprising only three genera, with five species, in North America. Five toes. _Desmognathus._–The tongue is attached along the median line, free behind, oval in shape. Three species in the eastern half of the United States. _D. fuscus_ is one of the lungless Urodela, for which condition see p. 46. The skin is nearly smooth; parotoids prominent, gular fold strongly marked. General colour above, brown suffused with pink and grey, sometimes with a dark lateral band; under parts mottled brown. The vomerine teeth are frequently absent. Total length, about 4 to 5 inches. They live, carefully concealed in the daytime, under {103}stones in or on the edge of the banks of little mountain streams. The eggs are laid in two long strings, and are wrapped round the body of the female like a rosary, the female having resorted to a hollow in the mud, below a stone or other suitable place. The outer envelope of each egg tapers out into a short stalk, and the several stalks all converge, or are glued together into one common knot, "much like a bunch of toy balloons held in the hand of a street vendor." The egg is said to be meroblastic. The larvae seem to remain in the egg until they are nearly adult, and they emerge at midsummer, with the gills already much reduced. The complete metamorphosis takes place in the autumn of the same year. These little newts can, according to Wilder,[48] be collected all the year round, in Massachusetts from March to December, except during the time of deep snow. They are nocturnal and are easily kept. [Illustration: FIG. 19.–_Desmognathus fuscus_; female with eggs in a hole underground. × 1. (After Wilder.)] _Thorius pennatulus_, from Orizaba, Mexico, the only species, is noteworthy for its extremely large nostrils, and for the tongue, which is supported by a central pedicle, free all round, and ending in a thick knob, which can probably be protruded. The limbs are weak, and the digits are also much reduced. Total length, under 2 inches, or 50 mm. _Typhlotriton spelaeus_, of the Rock House Cave in Missouri, is blind, the eyes becoming concealed by the skin during metamorphosis, when the gills are lost. SUB-FAM. 2. PLETHODONTINAE.–The five genera of this almost entirely American sub-family (only one species of which, _Spelerpes fuscus_, occurs in Europe) can be distinguished as follows:– I. The tongue is attached by its central pedicle only, is free all round, ends in a soft knob and can be shot out to a considerable distance. With 5 toes: _Spelerpes_, p. 104. With 4 toes: _Manculus_, p. 106. {104}II. The tongue is attached along the middle line and cannot be protruded out of the mouth. Jaws with numerous small teeth. With 5 toes: _Plethodon_, p. 106. With 4 toes: _Batrachoseps_. Maxillary and mandibular teeth few in number but very large. With 5 toes: _Autodax_, p. 107.