Wil/is.- — The Distribution of Species in New Zealand. 441 
Indian species 3*5, and those of wider dispersal 3*0. As these figures, 
or figures close to these, showed throughout the flora, family by family, and 
genus by genus, while at the same time every family and genus of reason- 
able size showed forms in every class from Common to Very Rare (i. e. 
occupying every size of area), in numbers increasing up or down, it seemed 
to me that the distribution of species in Ceylon was only explicable upon 
the hypothesis already mentioned. Nothing but a mechanical cause, 
acting equally upon all — or a combination of several causes, similarly acting 
without distinction upon every species or small group of species- — can make 
all the species behave alike. Some mechanical explanation must be found, 
and to me the only one that seems reasonable is age. 
In the case of New Zealand a similar splitting of the species may 
be done. East and south there lie several groups of little islands — the 
Chathams, Aucklands, Campbells, Antipodes, and Macquarie — which are 
shown by the soundings to lie in such a way that the flora common to 
them and to Australia must, in all reasonable probability, have passed 
through New Zealand. In other words, the wides which reach them ought 
to be extremely common in New Zealand, while the endemics which occur 
both in them and in New Zealand must have been developed at a very early 
period, and ought therefore to be very common in New Zealand also 
(common being used as a synonym for widespread). These predictions are 
both borne out by the facts, and afford very strong evidence in favour 
of the view that the wides are the oldest, a subject to which I shall 
devote a later paper. 
What I shall endeavour to do, then, is to show that the flora of 
New Zealand, like that of Ceylon, is distributed according to simple 
arithmetical rules ; and that its plants are grouped in the same general way 
as those of Ceylon, showing only such differences as may be predicted 
from a knowledge of my age and area hypothesis. In this way I shall 
bring forward yet further evidence, if such be needed, against the validity 
of natural selection, and at the same time strengthen enormously the 
probabilities in favour of my hypothesis of age and area. 
The flora of New Zealand, as given by Cheeseman, is thus made up : 
Table I. 
Filices (omitted in this paper) 156 
Coniferae ,, ....... 20 
Confined to the outlying islands, or to them and such countries 
as Australia, South America, &c. (omitted in this paper) . 91 
Total omitted here . . 267 
Confined to New Zealand (as defined) ..... 902 
In New Zealand and outlying islands only .... 98 
Of wider distribution, i. e. reaching Australia, South America, &c. 301 
Total . 1,568 
Total here dealt with . . 1,301 
H h % 
