60 



Mary Blount. 



Fig. 50. — Photograph of a living pigeon egg. The bird was Ivilled at 6 

 a. m., ten hours after fertilization of the egg. The photograph was taken 

 through a window in the shell at 6.45 a. m. Then the egg was incubated 

 until 11 a. in., when it was killed. A photograph from the whole mount of 

 the later stage of the egg is shown in Fig. 47. 



