426 BICKFORD. [Von. IX. 
These experiments showed that if there are any formative 
cells upon which the initiation of these regenerating processes 
depend, they are not restricted to any special regions, — when- 
ever a transverse section was made, a tendency to form 
hydranths was found. At the same time these experiments 
tend to show that the regeneration is more a process of trans- 
formation than new growth, as, where the stem portion to be 
transformed was too limited, abnormal forms often result, 
instead of a growth with a complete hydranth. From the last 
experiment described, the conclusion may be drawn, that the 
tendency to form oze complete hydranth of short pieces is 
rather more marked, than to form double abnormal forms. 
(ce) Later in the season, when most of the colonies were 
found to have lost their hydranths, experiments were made 
with stems and roots, to ascertain if under these conditions of 
a normal resting stage there was any concentration of regener- 
ative material in the roots. Twenty-two pieces of roots and 
twenty-six pieces of stem were placed in sea water. The 
lengths of the stems varied from 7 to 14 mm., while the pieces 
of roots varied from 1 to 4 mm. When these were examined, 
on the fragments of roots were found thirty-two hydranths ; 
when these branch, as only the roots do in this form, hydranths 
were found on each branch, thus illustrating beautifully the 
principle of heteromorphosis. 
The number of hydranths on the stems was only thirteen. 
The hydranths on the roots were much smaller than those on 
the stems, which follows naturally, as the diameter of the 
coenosarc determines the size of the hydranth. After several 
days the growth of the roots and stems was measured. The 
average increase in length of the former was from 4 to 5 mm., 
while the stems had grown only from 2 to 3 mm. As these 
experiments were not made when the colonies were in their 
most flourishing condition, it cannot be stated whether these 
results would hold good for a// conditions, or whether they 
indicate a concentration of growing material only during a 
resting period. 
