348 12 



C. taxifolia oder proliféra, im bewegten Wasser dürften sich gleichfalls Vorzüge 

 gegenüber den letzteren gelten machen." 



We shall now consider a little more in detail the great difference we meet 

 with in the assimilation-shoots of the West Indian forms of Caulerpa. We meet 

 with forms which, as C. proliféra, have a single large undivided leaf, we find forms 

 which like C. sertularioides and C. Asbmeadi have the leaf divided into numerous 

 round or clavate pinnules and further others such as C. taxifolia and C. crassi folia 

 where the pinnules are flattened, narrow in the former, broader in the latter. 

 Further we have species where the pinnules are placed on all sides round the 

 rachis, but wliere the pinnules are of very difîerent form, e. g. nearly cylindrical 

 in C. racemosa var. lœtevirens or swollen towards the top in C. racemosa var. claui- 

 fera, var. uvifera and var. occidenialis; or the pinnules are dichotomously divided 

 into thread-fine segments, e. g. in C. verticillata. 



hi this great multitude of forms we can distinguish the following two groups, 

 namely, the species in which the assimilators are leaf-like, bilateral, and the species 

 wliich have the pinnules arranged on all sides, constructed radially. vSvedelius 

 distinguishes the Ceylon Caulerpas in a similar way in these two groups, but he 

 has further a third type, the C. sertularioides-lype; he keeps this as a distinct group 

 especially because Caulerpa sertularioides, the only representative for it lives for 

 the most part in shallow water while the other bilateral forms of Caulerpa live 

 according to the observations of Svedklius in deeper water. As this is not quite 

 in accordance with my observations in the West hidies, as I shall show later on, 

 I will only maintain the two groups mentioned above. 



As we shall now consider a little more in detail the different forms belonging 

 to the two groups, we may at the same time try to find among the great richness 

 of forms of the assimilation-shoots, whether any adaptation to the surrounding 

 condition of life occurs. 



(1) Caulerpas with leaf-like, bilateral assimilation-shoots. That 

 the leaf-hke Caulerpas are derived from the radial forms which are certainly the 

 most primitive I quite agree with Svedelius. As Svedelius points out, we often 

 find on the same plant both bilateral and radial shoots, which shows that the two 

 forms are very nearly related, but we will further find on more thorough examina- 

 tion that several of the bilateral species are often radial at the base of the shoots. 

 In addition to the specimens mentioned by Svedelius, viz. : C. Lessonii, C. taxifolia, 

 f. tristichophylla and C. dichotoma, I have often found the same in the otherwise 

 distichous forms of C. cupressoides (Fig. 16 and 17), and in C. sertularioides f. Far- 

 lowii (Fig. 11). Even the markedly bilateral Caulerpa proliféra has by experimental 

 culture given cylindrical shoots, as Klemm (19, p. 468 — 9) has shown. 



We will begin with the examination of C. proliféra. This species occurs in 

 the West Indies partly in the littoral region and here even in the uppermost parts, 

 and in rather exposed but also sheltered localities, partly also common, as far as 

 I can judge from dredging, in deeper water. In shallow water and in somewhat 



