FIELDS AND GRADIENTS IN NORMAL ONTOGENY 345 



Fig. 163 



Differential acceleration in the development of the teleost fish Macropodus. 

 A, Control. B, Exposed to dilute atropin" sulphate for if hours during early 

 cleavage. Note large head, relatively shorter posterior trunk region. (From 

 Child, Physiological Foundations of Behavior, New York, 1924, after Gowanloch.) 



