354 18 



if it can occur at the surface (0.5 metre Berthold) yet seems to prefer deeper loca- 

 lities down to a depth of about 15 m.", then it appears from my investigations 

 that it does not hold good in the West Indies, where it is to be found in shallow 

 water on even rather exposed coast. Thorough comparative investigations in 

 nature can therefore yet give much important information. By means of these 

 and especially in connection with comj)rehensive experimental cultures, we can 

 first hope to get at the bottom of the variability of the Caulerpas and thus also 

 reach to greater clearness regarding the definition of the species. 



