133 



from shallow water have a very distinct periodical growlh, quite 

 in the same way as in C. crassifolia. 



Fig. 104 shows a small specimen from St. Croix, from which 

 island this species, as is well knowTi, was originally described and 

 which is quite like the specimens to be found in the Botanical 

 Museum in Copenhagen upon which Vahl founded his description. 

 They are in good accordance with the description of M"^^ Weber-van 

 BossE 1. c. and with the forma tijpica of Svedelius (1. c. p. 112), 

 Syn. Caulerpa jalcata Kiitz., Tab. phyc. Bd. VII, tab. 5, fig. V. 



This species is rather common on the shores of the Danish West Indies. 

 Geogr. Distrib. West Indies, Florida, Ceylon, Floris, and the Sand- 

 wich Islands. 



8. Caulerpa sertularioides (Gmel.) Howe. 



M.A.Howe, Phycological studies II, p. 576. F. Borgesex, 1. c, 1907, 

 p. 365. 



Fucus sertularioides Gmelix, Historia Fucorum p. 151, tab. 15, fig. 4. 



Caulerpa plumaris (Forsk.) Ag., Weber -van Bosse, Monographic 

 p. 294. 



Exsicc. WiTTR. & NoRDST., Algae exsiccatae, Nr. 1585. 



f. typica Bergs., 1. c. 



f. hrevipes (J. G. Ag.) Weber-van Bosse, Monographic p. 294. 



f. longiseta (J. G. Ag.) Weber- van Bosse, Monographic p. 295. 



f. Farlowii Weber-van Bosse, Monographie p. 295. (Fig. 106). 



Caulerpa sertularioides is a distinctly littoral alga which is 

 very common from the surface of the sea down to a depth of some 

 few meters. It occurs both on rather exposed coasts and in quite 

 sheltered localities. On exposed coasts it is partly f. typica, char- 

 acterized by its rather thick, not very densely placed pinnules, 

 partly forma brevipes that occur. They often grow in rather large 

 tufts sometimes together with other Caulerpas, e. g. C. taxifolia, 

 and wave to and fro in the swell. 



In localities where it is steadily exposed to some swell, e. g. 

 at the landing place at Christiansfort in St. Jan, I have found a 

 form distinguished by having a long and narrow leaf which I think 

 is to be considered as a wave-beaten form, similar to the forms 

 of C. racemosa var. occidentalis and var. uvijera with long erect 

 shoots I have found in the same locality and which will be men- 

 tioned later on. 



While the two above-mentioned forms are for the most part 

 to be found on more exposed coasts, forma longiseta, characterized 

 by its longer, thinner and densely placed pinnules, is especially 



