6 
Willis . — The Evolution of Species in Ceylon , 
Polygala , Garcinia , Stellaria, Impatiens , Rhamnus , FzVzk, Crotalaria , 
Desmodimn , Poterium , Begonia , Dipsacus , Vernonia , Senecio, Symplocos , 
Swertia , Ipomoea , Justicia, Coleus , Scutellaria , Piper , Loranthus , Ficus , 
Dendrobium , Habenaria , Smilax , Areca , Eriocaulon, Carex i Panicum , &c. 
It is absurd to suggest that all these genera commenced in Ceylon, and 
yet this must have been the case if the endemic species are the oldest, 
unless one imagine that these genera commenced polyphyletically at the 
numerous places where they exhibit endemic species. 
The chief objection to my views comes from the supporters of Natural 
Selection, and is simply a restatement of their position (which as yet lacks 
proof) that endemic species are local species developed in response to local 
needs or conditions. I have already dealt with this question in a series 
of previous papers, but it will be well to add further arguments here, 
and especially an arithmetical argument which appears to me of a very 
conclusive nature. 
We have seen above that all the families with fourteen or more 
endemic species, and all the groups of families with fewer, agree very 
closely in the degree of rarity of those species, which only varies between 
3-9 and 4*9. The mean rarity of the endemic species, from which no 
family departs very far, is 4.3. Now examination of the areas occupied by 
the various classes in Trimen’s Flora shows that Rather Rare species 
occupy on an average an area of about fifty miles in diameter, so that 
a rarity of 4-3 would indicate that the average area occupied by an 
endemic was about forty miles in diameter. Now in such an area, 
especially in the hilly south-west of the island, where the bulk of the 
endemics occur, it is impossible to talk of local conditions, for it includes 
every kind of soil, great range in local composition of flora, great differences 
of climate, and many other variations. This simple consideration alone 
makes a very strong case against Natural Selection. As I have elsewhere 
pointed out, why should a pinnate leaf suit one valley, and a simple one 
the next valley to it, in the same genus ? 
As Table II shows, the endemics increase in number down the scale 
from 19 Very Common to 233 Very Rare, while the species of wide 
distribution go in the opposite direction, and those of Ceylon and 
Peninsular India are fairly evenly distributed. Not only so, but in general, 
as we have shown, all the families with fourteen species or more, and all 
the groups of families with fewer, show the same thing. 
We may analyse the figures of Table VI of the Phil. Trans, paper, 
and exhibit the distribution of the endemics within each family in point 
of rarity, when we obtain the very striking result here shown : 
