Ocean-currents 55 



37 and 40 km. [23 and 25 miles]. To Java's Third Point the distance 

 is approximately the same ; and to the northern point of Prince 

 island it is 43 km. [27 miles]. 



Fruits and seeds of strand-plants may therefore be easily trans- 

 ported to the shores of the Krakatau islands by currents, which are 

 not constant in direction, from all the neighbouring - coasts of Java 

 and Sumatra as well as from the islands in the Sunda Strait and in 

 the Java Sea. The transport of floating plants and portions of plants 

 by the current which sets to the south-west can be accomplished 

 under favourable conditions in less than a day ; more especially is 

 this the case from the northern entrance to the strait, from the 

 Sumatran coast at Varkenshoek, the Zutphen islands, from the island 

 of Dwars in the channel, St Nicholas Point and Java's Fourth Point 

 on the coast of Java. During the east monsoon the direction of this 

 current remains constant for 18 hours ; in the broader and middle 

 part of the strait/ in the direction of Krakatau, its velocity is at least 

 3 km. [1*8 miles] an hour and thus a transport for a distance of more 

 than 50 km. [31 miles] is possible between two tides. Seeds and fruits 

 with feeble floating capacity may thus be carried direct to Krakatau. 

 It should be added that other possible means of transport such, for 

 example, as Guppy has described in reference to the colonisation of 

 the Cocos islands, are not excluded. 



Guppy has shown that small seeds of strand-plants such as 

 Tournefortia argentea, Scaevola Koenigii, Pemphis acidula, etc. 

 occur with sand in the crevices and cracks or in the holes 

 and burrows made by molluscs and worms in stems and branches 

 stranded on the beach. Seeds, like sand, are blown by the wind 

 into every available cranny. The stems and branches are again 

 floated off by high tides or storms and thus the seeds and fruits 

 concealed in the crevices are transported to new localities without 

 losing their power of germination. 



By this method of seed-dispersal it is possible, therefore, for 

 strand-plants, the seeds of which do not possess special floating capacity, 

 to take part in the colonisation of new coast-regions : inland plants 

 may be introduced by the same means. 



There are also other methods by which germs may be trans- 

 ported across water. 



Inundations and high tides on the coast and, in the interior, 

 swollen rivers frequently carry freshly uprooted trees into the sea. 

 The earth entangled in the mass of root above the surface of the 

 water may contain various seedlings and seeds,, also Grasses and 

 Cyperaceae ; epiphytes on the branches of the floating trees are out 

 of reach of the injurious effects of sea-water. By the same means 



