Factors in Regeneration 



339 



regenerates 33 per cent, the corresponding inverted stems of series 2 

 regenerates 8 per cent. Similarly, series 5 produces 36 per cent, 

 the inverted ones 7 per cent. The branches in the two sets are 

 too close together to warrant the belief that the difference in posi- 

 tion on the stems can account for the large difference in regenera- 

 tion. When inverted lateral branches do regenerate polyps, they 

 invariable turn upward. 



Embedding stems in sand affects regeneration just as a ligature 

 tied around the stem at the level of the sand would do, for in both 



TABLE 16 



kW 



Polyps reg. on 



Oral ends % 



Lateral ends 



3 days ■ ■ • \ Aboral f nds 33 



Total 33 



% % 0% 42% 



8 7 33 36 



58 66 



24 



18 28 



37 



8% 

 13 



H 



6 days . . . < 



Oral ends 



Lateral ends 



Aboral ends 74 



Total 



74 



140 



50 

 41 



73 



44 



55 



56 



35 



Total number of stems 72 



Total number of branches 281 



cases regeneration at the free axial end (oral or basal) of the stem is 

 stimulated. The number regenerated at the upper ends of these 

 stems depends on whether erect or inverted stems were used. 

 Regeneration at the basal ends of inverted stems is very much 

 greater than that at lateral or oral ends, for example, 58 per cent are 

 produced at the basal ends, 8 per cent at the lateral ends, o per cent 

 at oral ends, in one series. Again 66 per cent regenerated at basal 

 ends, 7 per cent at lateral and 42 per cent at oral ends ot a second 

 series. Furthermore, the total number of polyps produced on a stem 



