60 STAGING OF AMPHIBIAN EMBRYOS 



Eana pipiens series. These new photographs are offered as a supplement to 

 the drawings of the normal series. They were all taken through one ocular of a 

 tinocular microscope using a Mifllmca adapter with Micropan (Dupont) film, and 

 developed with Edwal 20 for contrast. Except for the last plate the pictures 

 are all enlarged to the same scale. The series is made complete in order that 

 Instructors may find specific structures at any stage of development. 



