98 C. M. Child. 



In all cases where the form of the pieces rendered it necessary 

 figures were drawn in my notes on the basis of the measurements 

 and the living specimen. By this means a record was kept not 

 only of the principal dimensions, but also of any special features, 

 e. g. the angle between the axis of the new and old tissues, the 

 curved contours, etc. The actual form-relations and contours are, 

 I think, shown by the figures as exactly as is possible in a case 

 where alteration of indiv^idual form is so great. Except where 

 otherwise stated the figures are about seven times the natural 

 size. The various internal organs are represented so far as 

 necessary in a conventional manner. 



REGULATION, NUTRITION AND USE OF PARTS. 



As a preliminary to the descriptive part of the paper a brief 

 discussion of certain phases of the problem in hand is desirable 

 in order to clear the ground. 



In no case was the attempt made to feed the pieces employed 

 for experiment. In consequence of the absence of food a marked 

 decrease in size occurred during the course of the experiments. 

 There is no doubt, however, that the results of feeding would be 

 similar to those obtained by Morgan with Planaria (Morgan, 

 'oo), for specimens were occasionally found among the worms 

 collected which had regenerated after a loss of a part of the 

 body. In these specimens the amount of new tissue formed was 

 much greater than in the pieces kept without food, and there is 

 no reason to believe that in pieces where regeneration is possible 

 growth to the full size may not occur, provided enough material 

 is at hand. As Morgan ('98 ) has pointed out, the material used 

 in the formation of new tissue in starving pieces is obtained from 

 the substance of the piece itself or from its reserve supplies, and 

 the bulk of the old tissue is reduced to a greater or less extent 

 by the formation of the new tissue. When the pieces are fed 

 the amount of new tissue formed is more or less increased and 

 the old tissues not only do not decrease in size, but may grow 

 larger. 



The fact that formation of new tissue may occur, not only 

 once but repeatedly, in pieces which have been for weeks without 



