13 349 



exposed localities the leaf is often narrow and it has often numerous proliferations. 

 This seems to be in good accordance with the observation of Janse (18) in the 

 Gulf of Naples where Caiilerpa proliféra has in recent years spread itself out into 

 some open, exposed parts of the Gulf. This is especially due to its many prolifera- 

 tions, which seem to be especially developed in turbulent seas and which when 

 torn off are an excellent means of distribution. On the other hand it is the broad 

 form, f. obovata (Fig. 5), we find especially in deep water and even if the prolifera- 

 tions are also fairly often to be found here they are far from being so common 

 as in shallow water. A form nearly as broad as the one figured occurs also on 

 the shores and that even in rather exposed places. The advantage of this broad 

 and flat leaf is evident, the surface of assimilation being larger, but on the other 

 hand this broad leaf also runs the risk of being lacerated when it grows in an 

 exposed place; this is also often the case in spite of the leaf in the West hidian 

 form being thicker and more leathery than in the European form. Svedelius' 

 description of the occurrence of Caulerpa proliféra is therefore not quite in 

 accordance with what is the case in the Danish West Indies nor in the Mediterra- 

 nean and the surrounding seas, where C. proliféra seems indeed to prefer deeper 

 water in sheltered places, but is also to be found in turbulent localities and in 

 shallow water. 



While C. proliféra thus has the leaf undivided but as mentioned often lacerated 

 and worn at the apex when living on exposed coasts, the other bilateral species 

 have the leaf divided into more or fewer parts which when they are growing in 

 exposed places may certainly be of advantage. 



Caulerpa taxifolia has the leaf divided into many linear wings. It occurs 

 commonly in shallow water both in sheltered and also in rather exposed places 

 and it is further found in deeper water. The leaves grow larger here and are 

 commonly without proliferations, just as the rhythmical growth characterizing the 

 plant in shallow water seems to be wanting here. But when Svedelius writes: 

 "It avoids exposed localities when it grows in the upper littoral zone", this is as 

 mentioned above not in accordance with its occurrence in the Danish West Indies 

 where it can grow in rather exposed localities. On the other hand, Svedelius' 

 remarks suit better Caulerpa crassifolia, a species occurring commonly in shallow 

 water in sheltered places, whereas on more exposed coasts it is seldom and onlj' 

 badly developed. In deeper water it is also to be found and here the leaf grows 

 larger and is without proliferations or rhythmical growth. 



Caulerpa Ashmeadi I have only found in deeper water in about 20 — 35 meters 

 depth; how far this species elsewhere also is only to be found in deeper water I 

 do nol know. Hauvey ( 16) does not mention anything about this matter. Caulerpa 

 Webhiana f. disticha I have likewise only found in deeper water in the Danish 

 West India, even down to a depth of about 50 meters, but it is to be found in 

 shallow water at other places. 



On the other hand C. sertularioides is a specially littoral alga only occurring 



