THE CEYLON SPECIES OF CAULERPA. 



129 



discovery of some transition forms between two Catderfa types need not necessarily result in the union of 

 these species. 



C. dichotoma has a different mode of growth to G. loetevirens f. laxa, for the former does not occur 

 on rocks in very exposed locahties, and the latter does. C. dichotoma is only to be found on sandy bottoms 

 in somewhat deeper parts of the httoral zone. 



Oeographical distribution. — Ceylon : Weligama (at a depth of about 1 to 2 m.) ! 



14.— CAULERPA CHEMNITZIA (Esper) Lamouroux. 



J. G. Agardh, Till. Algernes Systematik, I., p. 36. 



Syn. C. racemosa var. Chemnitzia. Weber v. Bosse, Monographic des Caulerpes, p. 370. 

 Few Caulerpas, as far as their definition goes, maybe said to be more difficult to diagnose than 

 C. Chemnitzia. 



It is really indisputable that the opinion — in the main — of the position of this form, as expressed 

 by Weber v. Bosse, is right : it is to be considered as a transition form between C. racemosa (Weber v. 

 Bosse sens, lat.) and C. peltata. Its distinguishing character is that, as a rule, it has branchlets of different 

 kinds, viz., partly cyUndrical ones at the base of the vertical axis, and partly, higher up, such as slowly 

 increase in breadth and are nearly trumpet-shaped. Pigs. 264and 27 show pictures of some which I 

 consider to belong to typical C. Chemnitzia. 



Fi g. 26. — C. Chemnitzia 

 (ESP.) LAM. (1 X 1). 



Fig. 28. — C. Chemnitzia (esp.) lam. 

 f. ad peltatam (1 x 1). 



Fig. 27. — C. Chemnitzia (esp.) lam. (3 X 1). 



A closer examination of this species shows, however, that it has not always these types of branchlets 

 but that it varies very considerably, and these variations may point in different directions. One type of 

 variation is to be seen in fig. 28 and fig 29 : the cylindrical basal axes are rather few, but on the other hand 

 the trumpet-shaped axes begin very early, and they constitute the majority of the branchlets, ultimately 

 to change — and it is this that is most noteworthy — into typical peltata branches with large discs and a 

 sharp hmit between disc and stalk (fig. 28.) Herein we can see a good example of the fact that C. Chemnit- 

 zia can go over to C. peltata and that the supposed relationship between C. Chemnitzia and C. peltata, as 

 supposed by former autliors, e.g., Decaisne, Zanardini, is fuUy justified. 

 49-06 



