10 



THE BIOLOGY OF THE FROG 



CHAP. 



the gills is doubtless dependent on the fact that they are 

 worked in for the purpose of absorbing food. 



The genus Triton is remarkable on account of the marked 

 sexual dimorphism which occurs in several of the species, 

 especially during the breeding season. The male of T. cris- 

 tatus at this time possesses a high serrated crest above the 



FlG. 5. Triton cristatus. i, female; 2, male as he appears during the 



breeding season. (After Gadow.) 



head and body, and is marked with conspicuous colors. 

 After the breeding season the dorsal crest becomes greatly 

 reduced and the coloration becomes more dull. The female 

 has no crest and is not so conspicuously colored as the 

 male, although she also becomes duller in color after the 

 breeding period is past. 



A close relative of the Tritons is the common newt 

 (Diemyctylus viridescens) of the northern and eastern parts 

 of this country. It is a pretty species, being colored an 

 olive-green, reddish or readish brown above, orange or 

 lemon-yellow below, and having a lateral row of scarlet 

 spots, each surrounded by a black ring. A variety, minia- 



