BIOLOGICAL STUDIES ON CORYMORPHA. 

 I. C. PALMA AND ENVIRONMENT. 



BY 



HARRY BEAL TORREY. 

 With 5 Figures. 



CONTENTS. 



Introduction. 



I. Description of C. palma. 



II. Habitat; food. 



III. Activities of the polyp. 



a. Muscular movements. 



b. Geotropism; axial ceUs. 



c. Locomotion; amoeboid cells. 



d. Circulation; cilia. 



IV. The young hydroid. 

 Summary. 



INTRODUCTION. 



This is one of a series of papers which deal with some of the 

 phenomena of growth, differentiation and development in 

 Corymorphay from different points of view. The study of de- 

 velopmental mechanics has long since ceased to consist merely in 

 an analysis of the development of egg and embryo. That 

 regenerative development must be included goes without saying; 

 and it is with the feeling that the normal activities not ordinarily 

 considered in the category of developmental processes should be 

 included also, that I have incorporated much of what may at first 

 sight appear to be purely physiological material. 



Corymorpha is an exceptionally attractive basis for such an 

 investigation. In the first place, it combines remarkable powers 

 of regeneration with a simple development from the egg, the non- 



