370 34 



sometimes to several forms, as Mme. Weber van Bosse herself indeed has empha- 

 sised over and over again. 



I have therefore given up trying to refer the single specimen to these, often 

 only very little different forms, and prefer to divide them into groups according 

 to the external conditions under which they live, at the same time pointing out 

 the forms which occur in the different localities. By means of my investigations 

 in nature I believe, namely, that I have come to a clear understanding, that the 

 different forms, for a great part at least, are only to be considered as ecological 

 adaptions to this or that locality, as they are greatly restricted to certain localities 

 each with its own peculiar conditions of life. 



Several of the forms which occur at each of the different locaUties may by 

 themselves be very diverse, so that one could perhaps entertain doubts whether it 

 was not most correct to consider them as separate species; but on the other hand, 

 they are commonly so connected with intermediate forms, often the same specimen 

 shows so considerable variation in the one or other direction, that it seems to me 

 until further information is obtained most natural to keep them together. We can 

 only settle the matter definitely by the help of artificial culture experiments, e. g. 

 transplant specimens from exposed to sheltered localities and vice-versa, an experi- 

 ment which would surely not be difficult in practice. Should it then appear that 

 a certain form even after having been cultivated for some time had not changed 

 its external form, it would most probably be right to consider such a fixed form 

 as a species. Unfortunately I only stayed a short time in the different parts of 

 the islands and it was therefore impossible for me to untertake such experiments. 

 Besides the large number of forms which were already referred by Mme. 

 Weber van Bosse to C. cupressoides, it cannot be denied that several forms referred 

 to other species also show an exceedingly great likeness with C. cupressoides. This 

 is, for example, the case with Caulerpa Lessohii f. tiiticorinensis described by Sve- 

 delius; it must be admitted that the figure of Svedelius (1. c. p. 117, fig. 12) shows 

 an exceedingly great likeness to C. cupressoides. Svedelius is of opinion that the 

 difference between the two species must especially be looked for in the fact that 

 C. Lessonii has a broader midrib up to 2 mm. in breadth, and as shoots with such 

 a broad midrib are now and then, though far from always, e. g. not at all in 

 the specimens in the herbarium of Agardh in Lund, present in the specimens of 

 Ferguson he has referred these specimens to C. Lessonii. Mme. Weber has con- 

 sidered Ferguson's alga as a form of C. plumifera which species Svedelius however 

 considers as a synonym to C. Lessonii. As I have no material of this form 1 shall 

 not discuss the matter further here; so much may be said: C. Lessonii and C. cu- 

 pressoides are in form very nearly related, as Svedelius also seems to suppose 

 when he writes: "It seems to me not improbable that perhaps several of these 

 forms classed by Weber van Bosse among the comprehensive C. cupressoides might 

 with equal reason be transferred to the Lessonii group". 



Further we have some forms which Mme. Weber van Bosse has referred to 



