PLATE LI. 



Class AMPHIBIA continued. 

 THE FKOG continued. 



FIG. 1. URINO-GENITAL SYSTEM : MALE, x 2. 



t. testis: c. corpus adiposum: e. vasa efferentia: k. kidney: a. 

 adrenal: u. urino-genital duct: s. seminal vesicle: r. rectum! 

 b. bladder. 



FIG. 2. URINO-GENITAL SYSTEM : FEMALE, x U. 



o. ovary : c. corpus adiposum : os. oesophagus : o.d. oviduct : k 

 kidney: a. adrenal: u. ureter: ft. bladder: r. rectum. (The 

 left ovary and corpus adiposum have been removed to expose 

 the kidney.) 



FIG. 3. STAGES IN THE DEVELOPMENT OF THE FROG. 



In figs. a. to h. the epiblast is shown by dark shading, the hypoblast 

 by light. 



