6 



PLANT-ANIMALS 



[CH. 



s. 



_ 



r~ 



S. 



II. 



- 



-^ --*. 



7-w 



Fig. 1. The distribution of the colonies of Convoluta roscoffensis on 

 the sea-shore. I. at spring-tidal periods (low water) : II. at 

 neap-tidal periods (low water). Though a colony remains fixed 

 in position, its size waxes with the spring tides and wanes with 

 the neap tides. C, C = the colonies. S. = sea 



