352 16 



rows, ir we go to more sheltered places or a litlle deeper, we find forma typica 

 with longer ramuli and commonly only 3 rows of ramuli. And finally In the 

 quiet and often dirty water of the lagoons we get forms the branches of which are 

 often distichous. 



There can scarcely be any doubt that these corresponding forms of the two 

 different species are due principally to the different degrees of light and exposure. 

 And when Svedemus writes about similar forms of var. clauifera (1. c. p. 90): 

 "That these various forms arise directly through the influence of light, so that, for 

 instance, obscuration favours the lengthening of the axes, while bright or intense 

 light causes shortening of the axis system, seems very probable", I can express 

 my agreement with this; but I believe that the different degrees of exposure 

 influence in the same direction. 



On the whole my observations agree very well with those of Svedelius from 

 Ceylon, who also found all the radial forms in the littoral region in shallow water, 

 where they are especially adapted to live in the intense light found everywhere 

 where the water is clear, while just the forms which live in the yet shallow, it is 

 true, but unclear water of the lagoons, show a distinct transition to the distichous 

 forms living in deeper water. 



That the Caulerpas must therefore be regarded as ecologisms in great degree 

 is I think clear from what I have mentioned. So far as I understood them after 

 repeated investigations in nature itself, they are highly variable and adapted to 

 particular growing places. That we also find other variations, however, which can 

 not be considered as ecological is quite true. Svedelius thus distinguishes 5 

 different kinds of variations besides the variations of adaptation. 



To obtain a final opinion regarding the variations of the Caulerpas on the 

 whole, more thorough investigations in the nature itself and especially experimental 

 cultures would be of great importance; before we have these we can for the most 

 part only make suppositions as Svedelius also points out. Page 99 he writes: 

 "This is of course a pure speculation, and for the solution of this, as of so many 

 similar questions toucliing variation in Caiilerpa, experiments and cultures are 

 necessary which the traveller in the Tropics has difficulty in arranging". 



It is only upon Caulerpa proliféra that detailed experiments have so far been 

 made; this species is as Svedelius expresses it "the physiological Caulerpa par 

 préférence". We know from these experiments as mentioned ' above that it is 

 highly affected by the different external conditions which are offered it, forms 

 can arise which one would never think belonged to this species. And concerning 

 the dichotomous form which Janse has found in the Gulf of Naples, Mdme. 

 Weber van Bosse writes (1. c. p. 279): "Ces formes sont très curieuses puisque 

 nous voyons ici s'elïectuer, sous nos yeux, une transformation si complète de la 



