PLATE 11 



EXPLANATION OF PIGUKES 



37 The ventral surface of the dorsal abdominal wall of a 44/9.0 frog tadpole to 

 show the position of the adrenals. 



38 The adrenal cortex of a 43/8.0 normal frog tadpole. Drawn from a whole 

 mount. Osmium-bicromate fixation. The specimen was killed 221 days after the 

 operative stage. Liver diet. X24. 



39 The adrenal cortex of a 55/0.2 albinous frog tadpole. Same fixation, age, 

 and diet as above. X24. 



134 



