Fig. 23-10. If one cell of a frog's egg is killed when the embryo is in the two-cell stage, only 



a half embryo develoos. 



Fig. 23-11. If a hair loop is tied in such a way as to separate the eel part.al ly "« ♦-»-«" 

 amphibian embryo, a partially double ("Siamese twins") embryo w.ll result If the ha.r loop 

 rpullei tightly enough to separate the two cells completely, two normal, half s.ze embryos 

 result. 



