298 



C. M. CHILD 



region, an increase in the capacity for the formation of wholes 

 is evident in the third set of series 28. 



In table 4 a number of series including the pharyngeal and 

 postpharyngeal regions are combined to show the results of regu- 

 lation of this region as a single piece, as compared with the 

 results when it is separated into two and four pieces. 



The results are clearly defined. The region as a whole pro- 

 duced 100 per cent, of normal wholes. When cut into halves 

 or into quarters the percentage of normal wholes decreases and 

 the percentages of teratopthalmic wholes and headless tails 

 increase. Moreover, it is of particular interest to observe that 

 while the whole piece produces 100 per cent, of normal wholes, 

 its anterior half, when isolated from the posterior half, produces 

 only 66.7 per cent, of normal wholes, though the same cells are 



TABLE 4 

 From several series. Worms 12 — 15 mm. in length, in good condition. 



