THE NEWT AND ITS ALLIES 



261 



Early Development of Urodela. The eggs of Urodela 

 are deposited in a gelatinous mass in water, and are 

 attached to submerged plants, or to other objects in the 



FIG. 12 FIG. 13. FIG. 17. FIG. 18. FIG. 19. 



FIG. 245. Developmental stages of Spelerpes bilinecitus. Figx. S-'J, neural 

 groove beginning to form; Figs. 10, 11, neural groove closed; Figs. 12, i;>, 

 head beginning to form; Figx. 14-lf>, tail formed, yolk absorbing; Fig. 17, 

 embryo capable of moving in egg membrane ; Fig. IS, embryo just able to 

 swim ; Fig. W, three days after hatching. The letters indicate the successive 

 stages. After H. H. Wilder, from "The American Naturalist." 



water, either singly or in masses, according to the species. 

 The eggs contain much yolk ; consequently the cleavage is 

 partial, and the embryo seems to develop on a small part 



