THE CEYLON SPECIES OF CAULERPA. 



W.i 



that occurs on the pearl-banks on ttie shells of the pearl-oyster (Margaritifera vulgar is), where it has been 

 collected by HoRNELL (Nov.. 1902). 



Besides these there occur also some other forms, which, however, are rare, and which 

 do not play any characteristic part in the vegetation. One, which I have called /. tristichophylla (fig. 5), 

 I have also observed together with specimens of the /. typica at Paumben (3-4-03). 



Fig. 4. — C. taxifolia (Vahl) w. v. p.. f . asplenioides Fig5. — C taxifolia (vahl) w.v.b. /. tristichophylla, n.f. 

 (Grev.) w. v. b.(1 xl). (1 X 1). 



From a horizontal axis with a predominant number of assimilators of the main type, shoots forth 

 a branch here and there with a few pinnules in three rows (fig. 5). It is, therefore, closely allied to 

 C. falcifolia, and constitutes one of the links between C. taxifolia and G. falcifolia, as predicted by Weber 

 v. Bosse. As /. tristichophylla has only a few assimilators with pinnules in three rows and, moreover, 

 only at the base, and as in all other respects it corresponds with C tox^/oZia, I have come to the opinion 

 that it must be classed under this species, the more as I agree with Reinke in considering that to 

 point out a link of this kind between two otherwise well distinct forms does not necessarily prove that 

 these extreme forms belong to the same species. I am therefore of opinion that in spite of this form 

 one is quite justified in maintaining both C. taxifolia and falcifolia as different species. Probably they 

 have a common origin. In reality one can observe also in, for instance, Harvey's specimen (Friendly 

 Islands Algae No. 70, Herb. J. G. Agardh No. 16,522 ), a few branches with pinnules in only two rows, 

 i.e. typical taxifolia branches, but for the rest all the others are provided with pinnules in three rows. 

 C. taxifolia stands in exactly the same relation to C. falcifolia as G. sertularioides to G. selago. G. taxifolia 

 t . tristichophylla is consequently analogous with G. plumaris f. Farlowii, Weber v. Bosse ("Monographie" 

 p. 295). 



As for the /. interrupta (fig. 6) it is a little deep-sea form from the pearl banks in 

 the Gulf of Mannar growing together with /. asplenioides on the shells of the pearl- 

 oyster. It is a reduced /. asplenioides with small, weak branches and small 

 assimilators, with the pinnules in groups on the main axis and branchless parts in 

 between. It is clear that it has originated in a maimer analogous with G. scalpelli- 

 formis f. intermedia : that is to say, that the point-growth of the assimUatora has 

 gone on rhythmically and hence similar formations have arisen, which can be best 

 compared with proliferations. The form seems to be more occasional, but is, how- 

 ever, of theoretic interest as being a form analogous with similar forms of otlier 

 species, as foi example G. plumaris f. umbellata, Weber v. Bos.=!B {loc. cit., p. 295). 



Geographical distribution. — Ceylon : local and occasional as at Matara ! (/. typica .'and /. aspleni- 

 oides!) in rock-pools ; Wehgama! (at a depth of about 2 m. inside the reef together with Halimeda gracilis) ■ 

 Colombo (/. typica, Ferguson Ceylon Algae, No. 80 !) ; Pearl Banks in the Gulf of Mannar ! (/. asplenioides 

 49-06 



Fig. 6. 



C. taxifolia 



(vahl) w. v. b. 



/. interru/pta, n. f. 



(1 X 1). 



