254 ZOOLOGY. 



the latter with compressed tail and aquatic. The necessity of further 

 sub-division has, however, become fully apparent, and the old distinction 

 into land and water salamanders no longer tenable as parallel to any 

 anatomical features. Thus, of the highly natural germs JS^otophtlwhius, one 

 species is the most aquatic of all American forms, and the other the most 

 terrestrial ; yet the two are so much alike in shape as to render it a matter 

 of some difficulty to distinguish them. Without attempting any systematic 

 arrangement of the genera of salamanders we shall take them up in 

 geographical order, beginning with those of North America. 



The genus Amhystoma embraces the greatest number of species and 

 those of largest size. Its characteristics are, the entire absence of teeth on 

 the sphenoid bone, the nearly transverse undulating line of vomerine teeth, 

 in a measure forming the chord of the arc constituted by the outline of 

 the upper jaw. The tongue is broad and fleshy, and entirely adherent 

 except at the very edge. The species are mostly stout and clumsy, some 

 of them, as A. j^iinctata, A. o'paca, and A. jeffersoniana, terrestrial in their 

 habits, with rounded tail and cylindrical toes ; others again sub-aquatic, 

 with a much compressed tail, and short, broad, flattened toes. The genus 

 is found throughout the United States, and across to the Pacific ocean, 

 peculiar species occurring in California, Oregon, and New Mexico. The 

 terrestrial species exude a copious, milky, viscid excretion, from all parts 

 of the body. The development of the larva of the best known species has 

 already been referred to. The lungs have a higher degree of organization 

 than in the other genera, being subdivided into cells of moderate size. 



The next genus is JV^otophthalmus, known by the ocellated spot on the 

 back in all but one species, the small rudimentary tongue, the absence of 

 teeth on the sphenoid bone, the arrangement of the vomerine teeth in an 

 acute V, as in the true Tritons, the densely granulose skin, the three 

 foramina in the side of the neck, &c. The best known species are, N. 

 viridescens {Triton dorsalis) and N. miniatus {Triton symmetrica). The 

 former species is exceedingly abundant throughout the United States, and 

 is entirely aquatic. It has even been kept for more than a year in a glass 

 jar filled with water, coming up to the surface from time to time to take in 

 a mouthful of air. In the spring of the year a broad fin becomes developed 

 along the back and tail of the male, and the feet enlarge with the addition 

 of a black cartilaginous mass on the toes and inside of the thighs, for the 

 purpose of enabling it to hold on to the female. This is done by clasping 

 her round the throat with the hind legs, and retaining the hold for some 

 hours, or longer, jerking her round in the water most unmercifully during 

 the whole time. A quantity of seminal matter is finally discharged, which, 

 becoming diffused in the water, fecundates the ova while still in the lower 

 part of the oviduct. The eggs are laid singly, of an ellipsoidal shape, and 

 invested by a very glutinous coat, by which it is attached to the middle of 

 an immersed leaf, which is then doubled over it by the exertions of the 

 female. The eggs, after remaining for some time in this way, finally give 

 birth to small larvae, the general character of whose metamorphoses is 

 much the same with that of the species already described. The male 

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