DEVELOPMENT AND DISTRIBUTION OF LEGUMINOSZ. 373 
examples of development in one region and transportation 
thence to other lands by sea currents in recent geological 
time. 
In this connection it will be instructive to quote Guppy’s 
summary of observations on Afzelia bijuga, as being typical 
of the origin of many other types in various countries, such 
as Acacia Farnesiana, Tephrosia purpurea, Entada scan- 
dens, and Ceesalpinia Bonducella. 
**(1) Assuming that the genus has its home in the African 
continent, and that the species have frequently a riverside 
station, it is argued that the distribution of the genus on 
both sides of that continent can only be explained by its 
dispersal by rivers from a centre in the interior. 
(2) Afzelia bijuga, a widely distributed shore tree of 
tropical Asia, occurs in Fiji, both at the coast and in the 
inland forests. 
(3) This double station is associated inter alia with a 
different buoyant behaviour of the seeds, those of the coast 
trees floating for long periods, while those from inland 
generally sink. 
(4) There can be no doubt that this widely ranging littoral 
tree has been dispersed by the currents, but the specific 
weight of the coast seeds is on the average, but slightly 
less than sea water; and it is to this fine adjustment, 
always liable to be disturbed by variations in the environ- 
ment, that the irregularities in the distribution of the 
species are to be attributed.”’ 
The slow distribution of certain genera across certain 
land blocks is also an important point to remember. A 
famous example is that of the endemic species and genera 
of West and Hast Australia, respectively. In each area 
here considered the species are numerous, nevertheless 
they are identical only in very rare cases. Certain genera 
