372 



C. M. Child 



development of the new pharynx is well advanced, the intestinal 

 branches posterior to the new pharynx are seen to be degenerating. 

 The course of degeneration differs somewhat from that described 

 above for normal animals. The branches appear broader and 

 further apart as if this part of the intestine had been stretched 

 longitudinally, and in all probability a mechanical elongation of 

 this part does occur in consequence of its function as a posterior 

 end and region of attachment. A few days later the branches 

 disintegrate completely and the debris, appearing as dark masses 



Figs. 7, 8, 9 and 10 



and granules on either side of the slender axial intestine, gradually 

 undergoes resorption until after two weeks or more (Fig. 8) 

 scarcely any traces remain. A slender axial intestine still persists, 

 however. The difference between the postpharyngeal region and 

 the remainder of the body is striking (Fig. 8) for in other regions 

 intestinal reduction has as yet scarcely begun. The sharp limita- 

 tion of this peculiar process to the postpharyngeal region of the 

 piece makes it certain that the disappearance of the lateral intesti- 

 nal branches is correlated in some manner with the " redifferentia- 

 tion" of this region from a prepharyngeal to a postpharyngeal 

 region. 



