2/2 C. M. CHILD. 



During the next twenty days the pieces showed a considerable 

 reduction in size in consequence of decreasing internal pressure 

 and the distal portions of the tentacles once more began to 

 shrivel. 



December 21. 97 days after section. Marginal tentacles in 

 all four pieces 34 mm. -)- 12 mm. of shrivelled tissue. 



It was evident at this time that the pieces were becoming 

 exhausted and the experiment was concluded. 



In these pieces a gradual reduction in the length of the ten- 

 tacles occurred during the first two weeks, then the tips began 

 to atrophy, thus reducing the functional portion of the tentacle 

 still further. When closure of the pieces permitted distension 

 the tentacles elongated again and the atrophied tips underwent 

 almost complete resorption. Still later, as the pieces became 

 exhausted and the temperature of the water became lower, the 

 tips of the tentacles once more began to shrivel and at the 

 conclusion of the experiment mere stumps remained. 



Reduction of the tentacles was also observed in C. solitaries 

 in many cesophageal pieces, i. c., pieces retaining 

 the tentacles and with the aboral end in the ceso- 

 phageal region (Fig. 8). In such pieces the oeso- 

 phagus united with the body-wall aborally as in 

 the pieces described in the preceding paper ('04^), 

 and except in cases where closure of the body-wall 

 across the end of the oesophagus occured, the 

 internal pressure was never reestablished. 



In one piece of this kind which closed aborally across the end 

 of the oesophagus after eleven days the marginal tentacles 

 decreased in length before closure from 2530 mm. to 1012 

 mm. and the labial tentacles from 10-12 mm. to 6-7 mm. After 

 closure the length of the marginal tentacles increased again to 

 about 20 mm. and that of the labial tentacles to about 10 mm. 

 Here the period of collapse was comparatively short and there 

 was no shrivelling of the tips of the tentacles. In another 

 cesophageal piece the marginal tentacles decreased in three 

 months from 35 mm. to mere stumps 3 mm. in length and the 

 labial tentacles from 12 mm. to 1.5 mm. In this case, as in 

 Series 19 above, the reduction of the tentacles consisted at first 



