BIOLOGICAL STUDIES ON CORYMORPHA. 2Q I 



ditions, such buds arising on heteromorphic pieces become 

 holdfast 



The-e fact- indicate that while the origin of the bud depends 

 upon a degree of disorganization in the original physiological 

 system, its fate depends upon a secondary physiological coordi- 

 nation with the hydranths between which it develops. The bud 

 .11 quires 'In- distinctive character of a holdfast, namely, its adhe- 

 siveni ss, indi -pendent of any influence of tin- -ul-tratum. It has 



;i pointed out already that a hydranth at one end of a pi 



i profound influence upon the differentiation that may 

 occur al the other end, depending on its own -ta^e ot dc\ elopim-nt 

 and it- di-tance from that end. In the V ligim--, then, there i- a 

 de\ eloping region between the two hy- 

 dr.mths whose differentiation is con- 

 trolU-d to some extent by them. An 

 intere-ting case of the coordination of 

 parts in a -hort piece developing as a 

 Y figure, i- represented in Fig. 15. A 

 m -u axis ai ri-Jit angles to the original Fjc 



a\i- ha- IMI n established. And the 



orientation of gonads and tentacles especially the latter i- 

 dearly a resultant of the redistribution of forces correlated \\ith 

 that ( liange. 



l-'i--ion may be considered as a special case of budding, depend- 

 ing upon the length of the heteromorphic piece in\ol\ ed. A- the 

 piece It 1 1- 1 hen- the tendency to bud vanishes, until the < ha rat ter- 

 i-tic of alhe-i\eiie-- alone remains. This indicates that the 

 region bei \\een the t\\o li\drantlis is still controlled by them, 

 while the constriction and the frustules on either side of i' 1 ig. 

 10) mark the incn-a-ing elYecti\ eness of their independence or 

 of the systems ot" \\hich they form important parts. 



It i- onl\ on heteromorphic pie. es of moderate length, ho\\e\er. 

 that li ion of thi- ty|>e ha- been ob-er\ed. Ju-t a- il ua- from 

 |-elaii\el\ -hort heteromorphic piece- only that the re\er-al- 

 de-cribcd in the pre\ ion- -cctioii were obiained, the proximal 

 elements ( >f tlu- longer jiiece- failing to produce holdfa-'- at the 

 \\oiind, so it ha- been only in the -horter heteromorphic pieces 

 thai llie column between the hydranth- ha- -ho\\ n any sign 

 budding, con-triciinn or fni-iule form.ition. 



