Factors 111 Regeneration 319 



respects. For practical purposes, stems that resemble each other 

 in size, number and size of branches, that come from similar 

 regions in the colony, and that are removed from their habitat 

 at the same time, will be called "similar stems." 



EFFECTS PRODUCED BY REMOVING LATERAL BRANCHES OR 



PEDICELS 



Experiment I. This experiment was undertaken to determine 

 whether stems, bearing lateral branches but with the pedicels and 

 their polyps removed, would regenerate a greater or less per cent 

 of polyps than stems with all the lateral branches trimmed oflP 

 close to the main stem. On one side of a large stem the branches 

 were cut off close to the main stem, while on the other side only 

 the pedicels were removed. From a second stem the lateral 

 branches were amputated on both sides; and from a third the 

 polyps only were removed. The records for each stem were as 

 follows : 



TABLE I 



Regenerated in 



3 days 6 days 



No. of stems Pedicels only Branches Pedicels only Branches 



removed removed removed removed 



t jj_ 2 11 3 



' 34 * y 3 4 * J 



, 3 7 



^ rr TT 



i''* 18 Xf 18 17 



r f, 24 10 3 4 21 



5' ° o4 T7 3^4 TT 



Total 24% 35% 42% 77% 



* The figures for each side of the stem given separately. 



The conclusion is obvious, viz: that colonies from zuhich all the 

 branches have been removed regenerate more hydranths than those 

 from which nothing but the pedicels and their hydranths were ampu- 

 tated. This conclusion was corroborated by later experiments. 



All the lateral branches were removed from stems used in the 

 succeeding experiments. 



