127 



This species has hitherto only been found twice in the sea around the 

 island of St. Jan and both times by Dr. Th. Mortensen, e. g. off Ramshead 

 on the south coast of St. Jan in about 50 meters and in the sound between 

 St. Thomas and St. Jan near the little island St. James in about 30 meters 

 depth. 



Geogr. Distrib. Seems to occur in all the warmer seas: The West 

 Indies, Pernambuco, Canary Islands, Red Sea, Japan, Friendly Islands etc. 



5. Caiilerpa prolifera (Forsk.) Lam. 



Lamouroux, Memoire sur les Caulerpes, p. 30. J. Agardh, Till Al- 

 gernes Systematik, I, p. 11. Weber-van Bosse, Monographic, p. 278. 

 BoRGESEN, 1. c. 1907, p. 359. 



Fucus prolifer Forskal, Flora eegypt.-arab., p. 193. 



In the West Indian material we can distinguish the following 

 two forms: 



f. oboi'cita J. Agardh 1. c. p. 11. (Fig. 100). The leaf oblong- 

 obovate, with few or very often with no proliferations at all. 



f. zosterifolia n. f. (Fig. 101). The leaves narrow lineate-lan- 

 ceolate, interrupted and very richly proliferous. This 

 form seems to be rather near the dichotomous form which 

 Janse has mentioned from the Gulf of Naples (Pringsh. 

 Jahrb. Bd. 21, p. 168—9, pi. 6, figs. 6 and 7). 



On the shores of the Danish West Indies Caulerpa prolifera 

 is to be found both littoral and in deeper water, and on exposed 

 and sheltered coasts. Forma ohovata I have especially found in 

 deeper water down to a depth of about 40 meters; the leaves are 

 here often quite without proliferations at all or if these are present 

 there are only some few. The leaves are broad and short, often 

 nearly ovate; at the apex they are often rather deeply emarginate. 

 Forma ohovata also occurs in shallow water near the shores and 

 on even rather exposed localities, I have e. g. found it on the south 

 shore of St. Croix rather near Sandy Point where there is often 

 rather a strong surf and the leaves were also distinctly marked 

 by it. It grows here on low-lying coral reefs in and a little below 

 the surface of the sea and swings to and fro with the action of the 

 waves. The leaf has here a somewhat smaller size, is rather thick 

 and of a leathery consistency, most likely an adaptation to the 

 exposed locality, while the specimens growing in deeper water are 

 thinner. Though it seems to me that the West Indian specimens 

 are throughout thicker than the specimens I have seen living in 

 the Mediterranean and surrounding seas, e. g. from the bay at 

 Ajaccio and especially in great quantity from the bay at Cadiz. 



