no 



CEYLON MARINE BIOLOGICAL REPORTS. 



and scarcely dentated and curving upwards, now short and broad, clearly dentated, but not curved. 

 Such different forms of lobes occur both on different leaves from the same rhizome and also on the same 

 leaf. Of forms that have already been described the main mass of my material resembles most closely 

 the V. intermedia, Weber v. Bosse, especially the specimens from the Mauritius (according to specimens 

 in Agardh's Herbarium in Lund, No. 16,431) sketched by Weber v. Bosse ("Monographic desCaulerpes," 

 PI. XXIII, Fig. 7 ). In Ceylon there are, therefore, transition- forms between /. intermedia and /. denti- 

 culata, but on the other hand I have never seen /. typica, Weber v. Bosse (C. scalpelliformis, J. G. 

 Agardh), a characteristic type that seems to be confined exclusively to AustraUa. 



Structure of the shoots. — Especially charac- 

 teristic of this species is the rich formation of 

 regenerating shoots, precisely as J. G. 

 Agardh (Till xVlgernes Systematik I., p. 13) 

 lias asserted of it. These arise either from 

 the points of the lobes, or from the median 

 part of the lamina. Fig. 2 b shows an 

 (\xample of this kind of regeneration. But 

 t lie leaves could increase in another way 

 too without there being any sharp differ- 

 ence in the shape of a petiole. It seems 

 to be such kind of regeneration to which 

 J. G. Agardh refers when in the description 

 of his C. scalpelliformis {loc. cit. p. 13) he 

 says : " Frondes saepe quasi innovatione 

 prolongatae, lobis in una parte innovationis 

 brevioribus, dein iterum longioribus," and a 

 very fine example of this can be seen in a 

 C. scalpelliformis (Herb. J. G. Agaedh, No. 

 16,425) collected by Harvey in Australia. 

 Another case can be seen in fig. 2 a. The 

 terminal point of growth of the leaf (once 

 situated at v) has after a short period of 

 inactivity, resumed its activity, whereby 

 the leaf has grown longer. This shows itself 

 most clearly in the fact that the leaf has 

 increased in breadth, so that the newly 

 formed basal part has become broader than 

 the upper part of the older portion of the leaf. (An example of the same kind is afforded by 

 Harvey's Plate XVII. in " Phyc. Australia" I.) 



A proliferation has consequently taken place without the previous formation of a petiole. The 

 leaves of Caulerpa show, therefore, examples of a continued and repeated apical-growth which is unknown 

 in leaves of higher plants, but on the other hand is known in leaves of ferns and lower plants. This goes 

 to prove the predominant shoot-nature of the assimilators, even if they have a shape analogous with leaves. 

 This apical growth, although rhythmical, seems to be rather undefined. From this it is easUy explained 

 why the leaves in this species can attain such a great length, greater than in any other Caulerpa ; and 

 it is such long growing forms that make up the /. intermedia. 



If we examine such a leaf more exactly, we shall always find that it shows regularly alternating 

 narrower and thicker parts, due to its development having gone on rhythmically, while the growing point 

 has not worked uniformly, but periods of relative rest have followed periods of more active increase : 



Fig. 2. — C. scalpelliformis (r. br.) w. v. b. (1 x 1). 



