120 CEYLON MARINE BIOLOGICAL REPORTS. 



Finally, with regard to the plant named C. fissidentoides (Ferguson, Ceylon Algae No. 161) in 

 the Peradeniya Herbarium its determination is quite impossible, owing to its insignificance and poor 

 condition. It seems to be closely related to such a form as C. plumulifera on PI. XXXI, fig. 2 (but not 

 fig. 3) in Weber v. Bosse's Monograph. On the other hand, it also seems to be very hke C. Freycinetii 

 var. pectiiiata (PI. XXVI. , fig. 3) and especially the specimens of this form from Koh Kahdat (Gulf of Siam) 

 collected by JoHS. Schmidt (No. 108) determined by Weber v. Bosse and now in the collections of the 

 Botanical Museum at Copenhagen. 



Geographical distribution. — Ceylon : Pearl Banks in the Gulf of Mannar (/. typica) collected 

 by J. HoRNELL ! South India ; Tuticorin (/. tuiicorinensis) collected by Ferguson (Ceylon Algaj No. 

 413) ! Indian Ocean : Pacific Ocean. 



9.— CAULERPA CLAVIFERA (Turner) C. Agardh. 



C. Agardh, Species iygarum, p. 437. 

 J. G. Agardh, Till. Alg. Syst. I., p. 36. 



Syn. C. racemosa v. clavifera. Weber v. Bosse, Monographie des Caulerpes, p. 361. 

 Exsicc. WiTTROcK ET NoRDSTEDT, iUga- exsiccatae No. 345. Ferguson, Ceylon Alga) No. 17. 

 f. macrophysa (Kiitzing), Weber v. Bosse, loc. cit. 



f. remota. The vertical axes and also the stalks of the branchlets more or less 

 elongated ; the branchlets separated by rather long intervals (fig. 14). This 

 form grows in deeper water. 



Caulerpa clavifera is the most common Caulerpa in Ceylon. It occurs in somewhat different 

 localities both on rocks and amongst corals, but especially amongst the latter, on both sheltered and 

 more exposed places AmcMigst corals, on spots with rich supplies of changing water it seems to reach 



its highest development, and it seems to be one of the very few 

 algae which can grow together with living corals and Actinians. 

 It grows in rather large tufts (fig. 13) with the horizontal branches 

 creeping amongst the Actinians, and with only the always short 

 vertical axes with their large sparsely scattered spherical branch- 

 lets sticking up above them. When it grows directly on stones 

 the roots are rather more numerously arranged as adhesive organs 

 and it becomes a form with a relatively fewer number of coarser 

 branches. Also the vertical axis can attain somewhat different 

 development in different localities. But what is so characteristic 

 of this form is, that the whole assimilation system, i.e., the spheri- 

 cal branches in general, is horizontally spread out in one level. 

 This can be seen best if we look at fig. 13. From the coarse 

 horizontal axis issue these vertical axes, but they are often ex- 

 ceedingly short, so that the spherical branchlets seem almost to 

 be situated directly on them. If, on the other hand, the vertical 

 Fig. 13. — c. davifera (turn.) c. ag.(1 X 1) ^xes are longer, they frequently come to Ue recumbent with the 

 spherical leaves directed only in one direction. A Caulerpa clavifera tuft seen from above conse- 

 quently shows only a mass of small green spheres without any clear arrangement of axis system 

 (fig. 13). It seems to me as if J. G. Agardh has best drawn attention to this in his description 

 of this plant ("Till. Alg. Syst. "I., p. 36) when he says: " Surculi breviores, magis ramosi et 

 intricati quam in plurimis. Frondes erectiuscuhe quoque saepe breviores. Hinc ramificatio multo 

 magis irregularis saepius adparet, surculis repentibus, frondibus erectis radicibusque non prope 

 distinguendis, sed in speciminibus exsiccatis quasi sine ordine invicein mixtis." It follows from this 



