114 



CEYLON MARINE BIOLOGICAL REPORTS. 



and /. irUerrupta at a depth of about 10 m.), also at Paurahen ! (South-India) at a depth of about 6 m. 

 (/. typica). Indian Ocjean. Pacific (/. asplenioides at Sandwich-Islands). Atlantic (the West Indies). 

 Not* that the closely allied C falcifolia has its distribution in the Pacific and on the coasts of 

 Australia. 



5 — CAULERPA SERTULARIOIDES (Gmelin) Howe. 

 Howe, Phycological Studies II., p. 576. 

 Syn. Caiderpa plumaris (Forskal) Weber v. Bosse. Monographie des Caulerpes, p. 294. 



Caiderpa plumaris, Ag. Murray, Catalogue p. 38. 

 Exsicc: Harvey, Ceylon AlgajNo. 61!; Ferguson, Ceylon Algae Nos. 3, 40 !; Wittrock et 

 NoRDSTEDT, Algse exsiccatae No. 344! 

 f. brevifes (J. G. Agardh). 



Weber v. Bosse, loc. cit. p. 294. 

 f. tongiseta (J. G. Agardh). 



Weber v. Bosse, loc. cit. 295. 

 f. umibellata (Weber v. Bosse) 

 Weber v. Bosse, loc. cit. 295. 

 Caulerpa sertularioidcs /. hrevipes (fig. 7) is a common littoral form at the surface of the water and 

 seems to prefer spots somewhat exposed, where it grows in company with other green algae, often in 

 thick tufts (fig. 8). So it occurs on the western, more exposed side of the GaUe reef, especiafly on the 

 flat coral rocks below the Star Inistion. On the surface it is often very short and the vertical axes often 

 do not attain more than 1 cm. in height. 



.a' 



^^^^. 



I'Sl 





Fig. 7.- C. serf ularioides (am..) HOWE f. hrevipes. Fie fi r ^.^t,.i„ ■ •_; . 



rn. , ■ n ,1 ■'■) f- brevipes (J. G. AG.). (1x1). 



f he leaves m C sertulancndes are often characterized by the same rhythm as I have already described 

 before m several other Caulerpas, e.g., C. scalpelUformis , crassifolia, and taxifoUa. The growing poilt 



after a period of rest begins a new activity, whereby the first formed 

 pmnules are very short and afterwards increase in size. As now the acti 

 vity of the growing-point lasts only a very short time and consequently 

 only a small increase in the leaf takes place each time, we thiis get the 

 characteristic /. umbellata (fig. 9), which is characterized at atoety giance 

 by Its external hkeness to C. veHicillata, in that the branches are arranged 

 hv the f».t .W / . ,, m tufts around the maan axis. Of course a sharp difference is constituted 

 by the fact that /. umbellata has the pmnules predominantly in two directions, in contrast to C 

 vemcMata. That /. umbellata, however, can also have them in several directions follows from Weber v" 

 Bosse's note (loc. ait. p. 295). vveber v. 



The two forms /. brevipes and /. umbellata are thus rather closely aUied to one another • they grow 

 promiscuously, and from the same rhizome there arise also both the one and the other form 



^J«" f- '^^'^^'^ (%-JO) characterized by its long, narrow pinnules in close rows, is not uncommon 

 on the shares of Ceylon. But it occurs scarcely ever, if at all, in the upper part of the littoral zone but 

 usuaUy in somewhat deeper water. It commonly grows,not together with /. brevipes, but. as far'as I 



Fig. 9. — G. serlularioideft 



(OM.) HOWE /. umbellata 



(w. V. B.). (1 X 1). 



