268 



C. M. CHILD. 



A gradual reduction in size of the shriveled portions, due to 

 slow resorption, occurs, and these parts may disappear almost 

 completely, leaving blunt, stump-like tentacles with only slight 

 traces of the dark atrophied tissue at their tips (Fig. 5). 



A few experimental data will serve to illustrate more fully this 

 process of atrophy and the conditions under which it occurs. 



Series 50. 



November 21 , 1902. - In three specimens of C. solitaruts the 

 aboral end was removed by a transverse cut (Fig. 6) and the 

 aboral half of the distal piece was split longitudi- 

 nally by several irregular cuts in order to render 

 closure impossible or difficult. In these pieces 

 the aboral end was reopened daily or on alternate 

 days in the manner described in a previous paper 

 (Child, '04^). 



Controls were obtained by removing the aboral 

 end from three specimens at the same level as in 

 /-K_ the experimental pieces. These controls were 

 allowed to remain undisturbed and the cut ends 

 closed in the usual manner. In all specimens, 

 both experimental pieces and controls, the ten- 

 tacles were measured in a fully distended condi- 

 tion before section. The marginal tentacles were 

 1 520 mm. in length, differing somewhat in dif- 

 ferent specimens ; the labial tentacles were 5-7 mm. 

 December 77, 1902. 26 days after section. Experimental 

 pieces. Reopened daily on alternate days, but sometimes be- 

 came more or less distended during the intervals, owing to ap- 

 proximation of the cut margins and plugging of the intervening 

 spaces with slime. During this time the tentacles have gradu- 

 ally decreased in length. Marginal tentacles 68 mm. ; labial 

 tentacles 3 mm. 



Controls. The tentacles remained collapsed for a day or two 

 after section, then, as closure of the ends proceeded, the internal 

 water pressure was established and the tentacles became dis- 

 tended. The length of the tentacles is about the same as before 

 section, viz., marginal tentacles 1 5-20 mm. ; labial tentacles 

 57 mm. 



FIG. 6. 



