131 



'A 



I 



I 



the land I have found it growing on Halinieda-gvdivel in about 

 10 meters depth. But its real home is partly the well-sheltered 

 places, especially the lagoons, partly deeper water. In the first 

 mentioned places it grows very commonly in 1 — 2 feet of water, 

 creeping on the soft bottom with its nearly thread-like rhizome; 

 a few times I have also found it growing on the roots of the 

 mangroves. In deep water, where it also finds a quiet growing 

 place, I have as mentioned taken it down to a depth of about 30 

 meters. 



While SvEDELius only exceptionally found a peri- 

 odical growth in his material from Ceylon, this is 

 very clearly present in the specimens from shallow 

 water in the lagoons (Fig. 102). On the other hand 

 I have not seen such a rhythmical growth in the indi- 

 viduals from deep water (Fig. 103), where the condi- 

 tions of life naturally are considerably more uniform 

 than in the lagoons. 



Two forms can be distinguished of this species. 



Forma tijpica (Weber-van Bosse, 1. c. p. 290) is 

 recognizable from having the pinnules nearly linear and 

 not narrowed at the base. 



Forma mexicana distinguished by having the pin- 

 nules a little narrowed at the base and broader at the 

 apices. The sinus between the pinnules is roundish. 



The two forms are very nearly related and inter- 

 mediate forms occur very often. 



Forma mexicana is the most common form on the shores 

 of the Danish West Indies and occurs in sheltered locahties 

 everywhere. In deeper water I have got it at St. Croix in 

 White Bay in a depth of about 10 meters, at St. Thomas in 

 the sea west of Water Island in about 20 — 30 meters and at 

 St. Jan off Christiansfort and America Hill in the same depth. 



Forma typica I have only found in the sea west of 

 Water Island in about 30 meters of water. 



Geogr. Distrib. The West Indies, Florida, Guyana, 

 Bermudas, Canary Islands etc., Red Sea, Indian Sea, Friendly 

 Islands etc. 



■^ 



Fig. 103. 

 Caulerpa 

 crassifolia 

 (Ag.) J. Ag. 

 In deep 

 water off 

 Christians- 

 fort! St. Jan). 

 (About 1:1). 



7. Caulerpa taxifolia (Vahl) Ag. 



C. Agardh, Spec. Alg. p. 435. Weber-van Bosse, Monographie p. 292. 

 BoRGESEN, 1. c. 1907, p. 363. 



Fucus taxifolius Vahl, Skrivter af Naturhistorie-Selskabet, t. V, 2det 

 Hefte, 1802, p. 36. 



9* 



