194 STUDIES IN GENERAL PHYSIOLOGY 
apical and b the basal end (root). «ab is suspended ver- 
tically in the aquarium so that both cut ends are surrounded 
by water; a is directed upward, 6 downward. Complete 
regeneration occurs, a new stem S being formed at a, while 
one or more roots W are formed at 6; the former grows 
upward, the latter down- 
ward. 
We repeat the same 
experiment with another 
piece of stem, only this 
time the basal end 6 is 
directed upward, while the 
apical end a is directed 
downward. <A stem S is 
formed at the basal end 
which is directed upward, 
while one or more entirely 
normal and growing roots 
are formed at the apical 
end which is directed 
ee downward (Fig. 48). Deli- 
cate lateral branches spring from the new stem which are 
directed slightly upward and carry polyps upon their upper 
surfaces. The new branch is an image of the old. In this 
way a heteromorphosis is readily brought about in Antennu- 
laria. 
4, If a piece of the stem of Antennularia is suspended, 
not vertically, but obliquely, in the aquarium (Fig. 44), a 
stem S which grows vertically upward arises from the upper 
cut end; from the lower end 6 spring roots which grow verti- 
cally downward; it matters not whether b is the apical or 
the basal cut end. Thus far this experiment shows nothing 
new. But branches S; and S;;, and roots W; and W,;, may 
arise from any other element of a stem put obliquely. The 
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