ON THE DISPERSAL OF PLANTS. 277 
one re ognises some belonging to trees such as Heritiera 
littore is, Cerbera Odollam, and Cycas circinalis, which, as we 
well know, prefer the sandy soil of a coral island. How 
comes it then, that these trees have not found a home on 
these islands, though their seeds and seed-vessels drift 
ashore? In replying to this question, I shall have to draw 
attention to the necessity, whilst studying the causes of the 
dispersal of plants, of inquiring into the agencies that destroy 
the stranded seeds and seed-vessels, and prevent their ob- 
taining a footing. The drifting seed, in fact, is comparatively 
safe on the open sea, but when it gets stranded on the beaches 
of the Cocos Islands and begins to germinate, it is at once 
destroyed by the crabs. Of the 50 or 60 different kinds of 
fruits and seeds found commonly amongst the vegetable 
drift on the beaches of these islands, not more than a dozen 
have succeeded in establishing themselves. The long im- 
mersion in salt-water may have injuriously affected some, 
but the majority are destroyed by the crabs. : 
I have es informed by the proprietor, that sometimes 
when a large amount of vegetable drift has been stranded on 
the beaches, a line of sprouting plants may be shortly observed 
just above the usual high-tide mark. The tender shoots are 
soon eaten by the crabs, and in a little time every plant is 
gone. Many of the seeds that germinate on the beach are 
beans. In fact, beans, varying in size from those of Entada 
scandens downward, form about one-third of the vegetable 
drift; but the crabs effectually prevent them from getting a 
footing. I have come upon stranded seeds and fruits that 
have been thus attacked and partly eaten. 
Many attempts have been made by Mr. Ross to establish 
the stranded seeds on the islands, but the crabs have nearly 
always succeeded in defeating his efforts. It was only after 
many unsuccessful trials that he was able to grow one of the 
large beans of Hntada scandens in his garden, where it is now 
flourishing. A few yearssince, he made a similar experiment 
with the seeds of Calophyllum inophyllum that had been cast 
up on the weather beaches. Several hundreds were planted, 
and many germinated and sprouted; but the crabs destroyed 
every shoot except one, which survived in a sickly con- 
dition. 
The square fruits of Barringtonia speciosa, which often 
arrive at these islands in a fresh state, not uncommonly ger- 
minate; but only in very rare instances do they escape the 
crabs. Although this tree has established itself on the islands 
of Keeling Atoll, it has not yet obtained a hold in North 
