350 14 



in shallow water; it is lo be found on rather exposed coasts where its finely 

 divided leaves wave to and fro in the water; it is a smaller form f. brevipes we 

 find here. In more sheltered places it grows larger and the pinnules are often 

 thinner, viz. f longiseta. 



As is seen from the above, it may for the West Indian forms of Caulerpa be 

 said that the bilateral forms occur both in shallow water and here not only in 

 sheltered places but also in exposed as in deeper water. The result of Svedelius' 

 investigations is as follows: "An examination of the occurrence of the larger 

 bilateral Caulerpa forms both in (Ceylon and on other coasts, where anything is 

 known of them, consequently shows that in any case they have not their main 

 distribution in the littoral zone — even if isolated specimens occur there - but 

 that this must be located in deeper and quieter regions". In order to reach this 

 result he excludes Caulerpa sertularioides from this group and considers it as a 

 special type. But when, we may well say, the most distinctly leaf-like Caulerpa, 

 C. proliféra, occurs littorally and that even in rather exposed places, and further 

 other species e. g. C. iaxifolia also have the same habitat, I can not see any obliga- 

 tory reason for considering C. sertularioides as a representative of a special group. 

 The result of my investigations is therefore, that the bilateral leaf-like Caulerpas 

 are to be found both in shallow water (in company here with the radial Caulerpas, 

 which, as we shall see later, are restricted to shallow water exclusively in Danish 

 West India and as it seems also elsewhere) and further in deep water where they 

 seems to reign alone. 



It has in this connection a great interest to see how the deepest-going forms 

 of the form-rich species C. cupressoides and C. racemosa behave in deep water. 



Firstly as regards C. cupressoides, referring for more detail to the systematic 

 part, it appears that, as we gradually pass from exposed coasts with intense 

 light to sheltered with more or less muddy, unclear water, the branches become 

 more and more distichous and we finally come to specimens from deep water, 

 20 — 30 meters, which are quite distichous, where even the branches are situated in 

 the same plane. 



C. racemosa behaves in the same way. Of this very form-rich species I have 

 some few times found a few distichous specimens in deep water in the Danish 

 West Indies which I have referred to the var. Lamourouxii. In accordance with 

 this, C. sertularioides, which always grows at least in the Danish West Indies in 

 shallow water, shows a disposition to be radial (f. Farlowii), and Svedelius found 

 a radial form of C. taxifolia, f. tristichophijUa, in a depth of about 6 meters it is 

 true, but this de[)th in the tropics is of no importance. Also C. Webbiana, the 

 f. disticha of which is found in a depth of about 50 meters at St. Jan is commonly 

 radial in shallow water even if f. disticlia is also found there. 



If we now ask whether the bilateral form can be especially useful for the 

 plants in deep water, it seems to me that this must be answered in the affirmative, 

 as the leaf, at least where a current is present even though feeble, will most pro- 



