360 



24 



most likely an adaptation to the exposed locality, while the specimens growing in 

 deeper water are thinner. Though it seems to me that the West Indian specimens 

 are throughout thicker than the specimens I have seen living in the Mediterranean 

 and surrounding seas e. g., from the bay at Ajaccio and especially in great quantity 

 from the bay at Cadiz. Kützing has also designated the West Indian form (Tab. 

 phyc. bd. 7, tab. 3rf) as "forma firma". 



Forma zosterifolia 

 ' • I have only found in 



shallow water from the 

 surface of the sea down 

 to some few feet. This 

 form is distinguished 

 by having a narrow 

 r --^ leaf of only about 5 — 



6 mm broad. It is as 

 a rule very richly proli- 

 ferous and shows often 

 a distinct twisting. 



This form grows 

 richly between sea- 

 grasses e. g. Thalassia 

 testudinum and Cymo- 

 docea manatorum in 

 shallow water in the 

 neighbourhood of 



Krause's Lagoon on the 

 south coast of St. Croix. 

 A very weak surf can 

 here enter from the sea 

 and in this the leaves 

 of Caulerpa proliféra 

 wave to and fro. 



From what has 

 been said above, it will 

 be evident that Svede- 

 Lius's supposition as to the mode of life of C. proliféra (1. c. p. 88) in the West 

 Indies is not in accordance with the facts. And as to its occurrence in the Medi- 

 terranean I can not quite agree with him. From the remark of Janse (18, p. 166) 

 that after a very strong gale in the Gulf of Naples he found great quantities of 

 Caulerpa proliféra washed ashore, Svedelius (1. c.) concludes that this alga is a 

 deep water form which cannot withstand a turbulent sea. He writes: "It is evident, 

 therefore, that if such broadleafed forms are to have any chance of living it must 



Fig. 5. Caulerpa proliféra (Forsk.) Lam. f. obovata J. Ag. 



In the sea to the west of Water island (St. Thomas). 



(About 1 : 1.) 



