152 



DEVELOPMENT OF THE FROG. 



some of them become collapsed, others for a time irregularly 

 dilated : the whole organ steadily diminishes in size, and in 

 tadpoles of 40 mm. (Fig. 35 KP) is not more than half its 

 former size. It now shrinks rapidly, and at the time of the 

 metamorphosis (Fig. 36 KP) has almost disappeared, all three 



Fig. 36. A Tailed frog, near the close of the metamorphosis, dissected 

 from the ventral surface to shew the kidneys and rej)roductive organs. 

 x4. 



A, dorsal aorta : F, fat body : GM, glomerulus : KA, archinephric or 

 segmental duct: KM, Wolffian body: KP, head kidney, disappearing: 

 KU, ureter : O, mouth : OR, genital ridge : RV, tip of ventricle : 

 TO, oesophagus, cut short. 



