i6o 



REGENERATION 



this way a new, artificial individual was made, as shown in Fig. 46, C, 

 with the middle part of the body in a reverse direction as compared 

 with the orientation of the two end-pieces. 1 The union of the three 

 pieces was so perfect that not even a swelling or a constriction indi- 

 cated the places of fusion. After six days a normal bud appeared at 

 the region of union of the posterior and middle pieces, that gave 

 rise to a new hydra, which separated after a few days. The com- 



FlG. 46. A. Two posterior pieces of hydra united by their oral ends. B. Two anterior pieces 

 of hydra united by their aboral ends. C. A " long hydra " made by uniting three pieces ; the 

 middle piece reversed. D. After Peebles. Two posterior pieces of brown hydra united by 

 oral ends, and one cut off near union. A new anterior end developed from the cut, aboral sur- 

 face. F. After Peebles. Union of a nutritive and a protective polyps of hydractinia. Subse- 

 quently former cut off at line, i-i. E. Union of two posterior pieces of hydra by oral ends. 

 Subsequently one piece cut off at line, 2-2. i. New head regenerated in region of union, 

 and a foot from aboral cut-end. 2 , E & . Fusion of two parts with a single hydra. 



pound animal was healthy and ate many daphnias. It was kept under 

 observation for twenty-four days, and appeared normal, giving off 

 several more buds. 



In other experiments of this same sort a foot generally developed 

 where the two aboral surfaces came together, and the head-end sepa- 

 rated from the rest of the piece. In another case a mouth and tenta- 

 cles appeared at the place at which the oral ends had united. 



1 This and other experiments were carried out by pushing the pieces on a bristle. 



