530 C. M. Child. 



system. Another exceptional case was that of a piece cut obHquely 

 at the level represented by the dotted line in Fig. 27. Twelve 

 pieces composed the series of which this was one. After about 

 five weeks it was noticed that eye-spots were present in this one 

 piece, and also that the amount of new tissue was greater than in 

 any other pieces of the series. Ten days later (forty-eight days 

 after section) the piece had attained the condition represented in 

 Fig. 42. No other similar case has ever been observed. The 

 regenerative power of this piece was as great as that of the best 

 pieces cut immediately behind the ganglia (A, Series 71, Fig. 18). 

 As regards the motor activity of this piece during early stages, 

 I can say nothing, since the pieces of the series were not examined 

 individually and compared, but after the piece had reached the 

 stage shown in Fig. 42 its motor activity was distinctly more 

 complete than that of the other pieces of the series. It was capa- 

 ble of more rapid progression and the margins of the new tissue 

 were used to some extent like those of a head. Fifty-eight days 

 after section the piece had attained the condition of Fig. 43; the 

 new tissue had increased still further in amount and the motor 

 activity of the piece, especially that of the new tissue, was greater 

 than before. Beneath the large group of eyes a small light area, 

 probably regenerating ganglia, was observed. It is very evident 

 that in this case there is an approach to regeneration of a head. 

 The new tissue is used as a head though in less degree than in the 

 normal animal. It is impossible to assign a definite reason for 

 the occurrence of this single case. In all my experiments nothing 

 of the sort has ever "been observed in other pieces at this level. 

 Moreover, this piece shows a degree of regeneration as great as 

 the best cases from levels immediately posterior to the ganglia 

 (A, Series 71, Fig. 18). Whether complete regeneration of the 

 head would have occurred could not be determined. Seventy- 

 eight days after section the piece died without having advanced 

 perceptibly beyond the stage of Fig. 43. Possibly if the piece 

 could have been fed complete regeneration might have taken 

 place. At all events this case is of great interest, since it indicates 

 that under certain conditions the amount of regeneration at a 

 given level may be much greater than the usual amount. Whether 



