.114 



CM. CHILD 



such cases ; posterior to it practically no changes have occurred in 

 the piece. 



^. In the above table only 56.7 per cent, i.e., seventeen of the 

 pieces formed heads at all: all the others died except one piece 

 which remained headless. X new pharynx appeared in 40 per 

 cent of the whole number, i. e., in twelve pieces. It is clear that 



7 



S 



9 



Figs. 7 to 9 Alcohol. Figure 7, piece including region between levels 5 and 8 

 in figure 1: regulation in water. Figures 8 and 9, similar pieces: regulation in 

 alcohol 1.5 per cent. 



the process of pharynx-formation is affected to a much greater 

 degree by the alcohol than that of head-formation for in five pieces, 

 16.7 per cent, heads but no pharynges appeared and in those 

 cases where the pharynx did form it was always very small and 

 remained so. Figure 8 represents the maximum regulation in the 

 set after ten days in alcohol : the head is normal and though smaller 

 than in similar pieces in water (fig. 7) is not extremely small, but 



