50 The Tree-toad, Hyla versicolor LeConte. 



as the period of development to hatching. The water-surface averaged 

 about 72 degrees. 



THE MATURE TADPOLE. 



Length of body contained 2.2 to 3.5 times in the tail, average 2.8. 

 Width of the body in its own length 1.3 to 1.7, average 1.47. Nostrils 

 nearer the eyes than the end of the snout. Eye lateral, visible from 

 the venter, and nearer the spiracle than the snout. Distance between 

 the nostrils 1.2 to 2.0 in interorbital space, average 1.63; in mouth 0.7 

 to 1.0, becoming equal about the time the arms are ready to push out, 

 average 0.878. Spiracle sinistral, its distance from the base of the 

 hind legs 1.5 times in its distance from the snout. Anus dextral. 

 Depth of the tail in its own length 1.6 to 2.6, average 2.1, seldom 

 under 2.0 unless the tip be broken or partially regenerated. Depth 

 of the muscular portion of the tail at its base 2.3 to 3.6 in the depth of 

 the tail. Mouth is contained 1.4 to 2.34 times in the interorbital 

 distance. Greatest length 50 mm. Greatest length of body 16 mm. 

 Greatest length of tail 32 mm. Greatest depth of tail 13 mm. 



Coloration of body (Plate ix, Fig. 1 H) : General color of back olive- 

 green. Background of back yellowish, covered with many fine hair-like 

 black markings and golden and black spots, becoming orange in the head 

 region and sometimes almost vermilion about the eye; the golden and 

 black spots are more pronounced toward the tail; on the sides is a 

 decided iridescence. The eye is slightly bronzy. The venter in general 

 is conspicuously white or light cream and slightly iridescent. The belly 

 is covered with fine golden spots. From the gill-region forward the ven- 

 ter is greenish, a coloration produced by black and golden spots. The 

 background of all the tail except the base is scarlet or orange- vermilion. 

 The base of the tail is like the body. The tail is covered with black 

 blotches, more prominent around the edges of the crests. These 

 blotches become much more numerous as the hind legs develop. 



Mouth-parts (Plate vm, Fig. 8) : Upper labium with two series of 

 teeth, the boundary fringe of teeth and a second lateral row on either side. 

 The median space between this lateral series is half of or less than the 

 length of one of the lateral rows. There are three continuous rows on the 

 lower labium; at times they are quite wavy. Papilla? and labium are 

 sometimes more or less punctulate with black dots. The second row 

 of papilla? extends across the lower labium beneath the third row of 

 teeth, not terminating at its ends as in the five species of Rana. The 

 upper fringe is rarely broken, although it occasionally is separated at 

 the middle or resolved into three parts. The lateral series of teeth 

 almost bridges the normal median space in some specimens. In 63 

 tadpoles the lateral upper row of one side was missing in but two speci- 

 mens. In one tadpole the lower first row was absent; in two or three 

 the second lower was in several parts or with one side gone; and in 

 one specimen the lower third row was almost gone. 



