ORGANIZATION AND GROWTH 201 



nally lay opposite de, and from the lower cut end a of the 

 stem. When the new stem had attained the length de, 

 I turned the whole animal about its axis, so that b and e 

 were directed downward, and the specimen was in the posi- 

 tion indicated in the drawing. The stem de ceased to grow, 

 and a delicate root W l , growing downward, was formed at 

 e. The drawing was made soon after the root began to 

 grow. Besides being formed at e, roots W 5 also grew from 

 the apical cut end b which was directed downward ; the three 

 stems $ 2 , $ 3 , $ 4 , were formed upon the upper surface of 

 the stem with their corresponding roots W 2 , W 3 , W. 



5. In all these experiments one fact which is, however, 

 not a specific property of Antennularia constantly repeats 

 itself : new growths arise much more easily and numerously 

 from the basal than from the apical end. I have observed 

 the same fact in Actinia mesembryanthemum, and A. von 

 Heider mentions it in connection with Cladocora. 1 



In general, too, the formation of roots in Antennularia is 

 dependent upon the formation of a stem. If a stem is 

 formed at any point, roots also form after some time, at first 

 upon the under surface of the old stem, then upon the upper 

 surface in the immediate neighborhood of the new stem, 

 and finally at the lower end of the new stem itself (Fig. 40). 

 It is self-evident how such phenomena complicate the 

 influence of orientation upon the place where new organs are 

 formed. 



6. I cannot say precisely how the position of the new 

 organs formed in Antennularia is determined by the orienta- 

 tion of the animal toward the center of the earth. Naturally 

 the effect of gravitation cannot be different in animate from 

 what it is in inanimate nature, and there would be no reason 

 for being disappointed should it be found that the apparently 

 mysterious effect of gravitation upon organization in Anten- 



1A. VON HEIDER, Wiener Sitzungsberichte, Vol. LCCCIV, Part I (1881), p. 664. 



