534 C. M. Child. 



54 is of interest; growth was probably more rapid in the lateral 

 regions in consequence of the presence of nerve cords and perhaps 

 also because of the presence of the pharyngeal pouch and the 

 almost complete absence of parenchyma in the median line. A 

 similar duplication was observed in a number of cases of this kind, 

 but was in all cases only temporary, disappearing completely in 

 later stages. 



A month after the second operation all five of the pieces pre- 

 sented about the condition shown in Fig. 55, the differences being 

 slight. No further regeneration occurred. 



Here, as in Series 75, there is no physical obstacle to growth, 

 such as Schultz believes to exist, yet regeneration of the head does 

 not occur. 



These two series show clearly that the explanation of the 

 absence of anterior regeneration given by Schultz for L. atojnata 

 certainly does not apply to L. tre?neUaris. There is little doubt 

 that the conditions in L. atornata are similar. Apparently the 

 cut surface in L. atornata contracts to a greater extent after section 

 than that of L. tremellaris but repeated section in the manner 

 described would undoubtedly leave open cut surfaces sufficient 

 for the occurrence of regeneration. 



These two series are also of interest in connection with the 

 question discussed in the preceding section, viz: the relation 

 between the level from which regeneration occurs and the amount 

 of regeneration. The level of the anterior ends in Series 75 is 

 just anterior to the pharynx while in Series 76 it is the middle of 

 the pharyngeal region, i. e.^ much further posterior. At the time 

 of the second operation, eight days after the first, the amount of 

 regeneration is greater in Series 75 (Fig. 44) than in Series 76 

 (Fig. 51). Ten days after the second operation a similar differ- 

 ence between the two series exists (compare Figs. 45-47 with 

 Figs. 52-54) and the same is true of the final stages a month later 

 (compare Figs. 48-50 with Fig. 55). As regards motor activity 

 a distinct difference between the two series was noted. Series 75 

 being the more active and capable of somewhat more coordinated 

 movement. The differences in activity between the two series 

 were noticeable, chiefly in the later stages. These facts agree with 



