74 C. M. CHILD. 



tion and has adopted a modification of the Aristotelian idea of an 

 entelechy as the basis of organic form. 



SUMMARY. 



1. The inrolling of the margins and the closure of openings 

 by contact of the inrolled margins is the result of the elasticity of 

 the body-wall. This elasticity must be greater in the inner por- 

 tions than in the outer portions, in order to produce the results 

 observed. The facts indicate that the mesogloea plays the most 

 important part in this elastic contraction. 



2. Openings between folds of the inrolled body-wall may be 

 stopped by the ectodermal slime secretion. This method of clo- 

 sure often occurs in pieces before the formation of new tissue 

 and permits the existence of considerable water-pressure in the 

 enteron. 



3. Contact or close approximation between two cut surfaces 

 or parts of a cut surface is a necessary condition of the growth 

 of new tissue from these surfaces. A single exposed cut surface 

 may heal over but no further growth occurs from it. 



4. The new tissue having arisen at a point of contact between 

 two cut surfaces is capable of extending in the form of a thin 

 membrane for a certain distance between diverging cut surfaces ; 

 the distance to which it extends is determined in a given species 

 by the angle of divergence of the cut surfaces, and in different 

 species by the thickness and quality of the membrane. 



5. The new tissue rising between two cut surfaces behaves in 

 certain respects as if subject to the laws of capillarity. 



HULL ZOOLOGICAL LABORATORY, 



UNIVERSITY OF CHICAGO, September, 1903. 



BIBLIOGRAPHY. 

 Child, C. M. 



'033 Form- Regulation in Cerianthus, I. The Typical Course of Regeneration. 



Biol. Bull., Vol. V., No. 5, 1903. 



'O3b Form- Regulation in Cerianthus, II. The Influence of Position, Size and 

 other Factors upon Regeneration. Biol. Bull., Vol. V., No. 6; Vol. VI., 

 No. I, 1903. 



Loeb, J. 



'91 Untersuchungen zur physiologischen Morphologic, I. Heteromorphose. 

 Wiirzburg, 1891. 



