of the Galapagos Archipelago. 253 
Polynesian species not found in America, it is perhaps the more probable that 
they migrated from the eastward into the Galapagos*. 
The means of transport which may have introduced these plants are, oceanic 
and aérial currents, the passage of birds, and man. 
To the first of these divisions the majority of the littoral species may be 
referred ; they are about 20 in number, chiefly such as are common to most 
warm latitudes, as :— 
Cissampelos Pareira. Avicennia tomentosa. 
Tribulus cistoides. Scevola Plumieri. 
Tephrosia littoralis. Ipomea maritima. 
Rhizophora Mangle. Calystegia Soldanella. 
Verbena littoralis. Heliotropium Curassavicum. 
To the non-littoral species, also possibly introduced by marine currents, 
belong the greater part of the remaining Leguminosew, the Boraginec, Verbe- 
nacee and Solanee. These and the above have seeds too large for probable 
transport by winds; they possess no means of attaching themselves to birds, 
&c., whilst the indurated seed-coats of some, and the exalbuminous embryos of 
many, probably aid them in resisting for some time the effects of salt water. 
It is only such species as have small seeds, or in which these are furnished 
with wings or other appendages, that offer aids to the transport by winds; 
they are few in number: such are Gossypium, Baccharis and Ageratum, the 
caryopsides of which last are, singularly enough, in £his group only deprived of 
pappus. Lobelia Xalapensis, Scoparia dulcis and the Urticece have very small 
seeds. 
That birds are active agents in transporting species may be presumed from 
* The more clearly to show the discrepancy between the Floras of the Pacific and Galapagos, I may 
mention that I have examined that of Malden Island, the nearest of the Tropical Polynesian Islands 
to the Galapagos. Most of its species are very abundant over all the tropical South Sea Islands, and 
none are absolutely peculiar: they are, 1. Phymatodes vulgaris; 2. Davallia solida; 3. Eragrostis, sp. ; 
4. Guettarda, sp. ; 5. Euphorbia ramosissima ; 6. Achyranthes velutina ; T. Boerhaavia ; 8. Lepidium pisci- 
dium; 9. Sida; 10. Ozalis corniculata; 11. Tribulus cistoides; 12. Crotalaria; 13. Portulaca; 14. Talinum 
pen 15. Coprosma, sp.; of which only the Tribulus, and perhaps the Portulaca, are Galapageian 
whilst even the Ferns and 8 of the 15 genera are not so. This, coupled with the fact stated "EN 
tiat there is no species an inhabitant of the Galapagos and the old world, that is not equally fusi 
in the new, are conclusive against the probability of any direct migration from the westward. 
212 
