* 
IIIO . The American Naturalist. [December, 
Fic. 4.—Dorsal and ventral view of a larval Diemyctylus the last of 
September and first of October, after it has become entirely terrestrial and 
was gradually assuming a bright red color. 
1G. 5.—Enlarged vermilion spot with complete black ring. 
Fic. 6.—Ventral view of a red Diemyctylus taken in the spring, and 
either two or three years old. This light yellowish-red color is very common. 
The enlarged vérmilion spot (Fig. 5) is to show that in animals of this size 
and in the adult the vermilion spots are usually entirely surrounded by 
a black pigment ring. 
F 
IG. 7.—Lateral view of a red Diemyctylus, to show the difference in, 
coloration of the dorsal and ventral portions of the body. By comparing 
with the viridescent forms it will be seen that the deeper coloration corre- 
sponds in situation in the two. The darker red shown in this figure is perhaps 
more common than the color in Fig. 6. 
FIGs. 8, 9, and 10.—-Views of an adult male Diemyctylus in October. 
It was in this specimen that pharyngeal respiration under water was 
first noticed, in 1886. The color varies considerably, some being darker and 
some lighter than here shown. 
Fig. 8.—Dorsal view. The number of vermilion spots is seen to be few 
and to differ on the two sides. As shown by the different figures on this 
plate, the number of vermilion spots varies considera 
Fic. 9.—Ventral view, showing the dark, horny rair on the tips 
of the toes, and the ridges (commonly six) on the inner or opposing surfaces 
of the legs. These horny developments mostly disappear during the sum- 
mer, immediately after the breeding season, and reappear in the autumn. 
IG. 10.—Lateral view, showing the tail-crest or fin, extending on the 
dorsal side to about opposite the pelvis, —not to the head, asin the European 
Tritons. This fin is less marked in the female (see Fig. 12), and partly 
disappears after the breeding season. The cloaca is partly everted, and 
shows some of the lining fringes or villi. The floor of the mouth and 
pharynx are depressed as when filled with water or air in pharyngeal 
respiration. Compare Fi i 
Fic. 11.—Lateral aspect of a gravid female. This coloration is frequent 
in adult forms found in water. The hind legs and the tail fin are smaller 
than in the male. The pharynx and floor of the mouth are raised as in 
expiration,—z. e., when the air or water is entirely expelled. 


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