ORGANIZATION AND GROWTH 193 
roots. Light has nodemon- ¢  strable effect upon the 
Even when lighted from 
continue to grow upward; 
the dark.’ Contact stim- 
tation. When the roots 
orientation of Antennularia. 
one side only, the animals 
and the same occurs also in 
uli, however, affect the orien- 
FIG, 40 
are brought in contact with a solid body, they attach them- 
selves to it and grow over itssurface. The stems and branches 
do not possess this 6 
form of irritability. Ap ls 
. With th - \e~ 
3. Wi ese pre 7 N\ ‘ 
Se 
L 
——s 
liminary remarks, I 
shall show how regen- 
eration and heteromor- 
phosis depend upon 
the orientation of the 
ell fo ft 
Wt 
4 
/ 
« YY JIN 
Y AWN 
JN 
aa 
w bi 
FIG. 41 FIG. 42 FIG, 43 
stem with reference to the horizon. ab (Fig. 42) represents 
a piece cut from the stem of an Antennularian; a is the 
1The specimen grew only slightly in the dark. This may, however, have hap- 
pened only by chance. 
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