208 
ORIGIN OF LIFE IN AMERICA 
The flora of the Cape Region is sub-tropical, a considerable 
proportion of the plants being West Indian. There are also a 
few genera which do not occur elsewhere on the American 
continent or the neighbouring islands. A small tree abun¬ 
dant in the Cape district belongs to the genus Albizzia, which 
is otherwise confined to Australia and the warmer parts of 
Asia and Africa.* Although the lower Californian species is 
quite distinct, its occurrence there might be attributed by 
some naturalists to accidental distribution by marine currents 
during some former period. No other occasional means 
of transport could be thought of. But Albizzia is by no 
means an isolated instance of floristic relationship between 
the countries bordering the west and east sides of the Pacific 
Ocean. Difficult problems of distribution of that nature are 
apt to be looked upon as instances of accidental dispersal. 
Yet these puzzling cases of distribution often supply us with 
valuable clues with reference to possible changes of land and 
water that may have taken place. That the Cape Region of 
Lower California is really a fragment of an ancient land-mass 
is suggested by the occurrence there of the burrowing lizard 
Euchirotes, of two species of the fresh-water oligochaet worm 
Kerria, and by a good many other faunistic features. Kerria 
is only met with in that region, in the West Indies and in 
southern South America. 
Among the most interesting members of the Cape fauna 
are the land shells of the genus Bulimulus above referred 
to. Dr. Cooper,*j* in his series of valuable papers, only 
mentions a few species found in that region, but he 
alludes to the noteworthy fact that two of the Bulimuli 
only live on the peninsula of Lower California, and in a similar 
situation on the coast of southern South America, though quite 
absent from the intervening moist tropical region. Dr. Dall,J 
and more recently Dr. Pilsbry, have shown, however, that the 
Cape species are not identical with the South American ones, 
though extremely like them in general appearance, and that 
they, together with those of southern Mexico and the interven¬ 
ing islands, form a group by themselves. About twenty species 
* Brandegee, T. S., “Flora of Baja California,” p. 222. 
t Cooper, J. G., “ Molluscs of Lower California,” p. 99. 
| Dali, W. H., “ Bulimulus in Lower California.” 
