ii8 



PATTERNS AND PROBLEMS OF DEVELOPMENT 



genital organs. Ectodermal susceptibility of adults decreases from the 

 posterior end anteriorly, with a slight increase at the anterior end in most 

 individuals (Watanabe and Child, 1933). The CO2 gradient represents, of 



Fig. 36. — CO2 production of Stylochus ijimai divided into three pieces, A, B, CD; extreme 

 anterior and posterior ends discarded; five series of determinations, each lot consisting of three 

 pieces from the same body-level; ordinate, thousandths of a milligram of CO2 per gram per 

 minute; abscissae, body-levels. Horizontal broken lines indicate CO^ production of intact ani- 

 mals, upper curves, CO, production immediately after section, lower curves, COj production 2, 

 4, and 6 hr. after section (from Watanabe and Child, 1933). 



