340 



A. J. Goldfarb 



depends on how much of it is embedded in sand. The deeper the 

 inverted stems are embedded, the proportionally larger total num- 

 ber is regenerated and vice versa. On the contrary, the deeper 

 erect stems are embedded the proportionally fewer polyps produced. 

 Experiment 75. These conclusions were corroborated and 

 extended by the following experiment in which the sand was 

 banked at an angle of 45° to the horizontal. 



TABLE 17 



Polyps reg. on 



in I Oral ends . . , 



Lateral ends 

 3 days . . . ■; Aboral ends 



6 days . . 



25% 



54 



Total 50 



Oral ends 50 



Lateral ends .... 79 



Aboral ends 



Total 75 



80 

 50 



96 

 50 



25% 50% 

 75 75 



73, 



50 



94 



150 



50 

 70 



75 



50 



90 



95 



116 



66^ 

 66 



66 

 66 



^ . ^ ^ ^ ,_ 



50% 

 56 



57 



83 

 9^ 

 116 



50 



77 



93 



SUMMARY. 



Hydranth bearing branches turn toward the zenith whatever 

 the position of the stem, tuhether erect, inverted or inclined. Erect 

 stems embedded in sand regenerate the largest total number of 

 polyps, inclined stems less and inverted the least number. Regen- 

 eration at the oral ends and lateral ends of similar inverted stems is 

 largely inhibited, but at the basal ends is remarkably stimulated. 

 It will be recalled that the coenosarc withdraws from the distal 

 cut ends of erect stems; but a ligature or its equivalent embedding 

 in sand, causes the coenosarc to move upward and regenerate 

 an oral polyp. On inverted stems the coenosarc under these 

 influences, and particularly under the influence of gravity, with- 

 draws not only from the distal end but from nearly all the lateral 

 ends, toward the upturned basal end, resulting in an immense 



