198 Willis. — The Relative Age of Endemic 
thus confronted with a very remarkable case when we deal with such 
a gigantic and universal genus as Senecio , which has hundreds of endemic 
species in all corners of the earth — Ceylon, New Zealand, Peru, Europe, 
North America, &c., &c., as well as hundreds of species occupying inter- 
mediate areas, and a few occupying large ones. Where did the last-named 
come from, and at what particular size does a species cease to be one of the 
doomed, and become an extending and conquering species ? Take the 
case of Cordia. in Ceylon. C. Myxa , which occurs all over the eastern 
tropics, is C (common), but C. monoica , which only occurs in Peninsular 
India, is also C, while C. Rotkii, which occurs in Peninsular India, Arabia, 
and Abyssinia, is only R, and C. subcordata , found on most eastern tropical 
coasts, is VR. C. monoica is only endemic to a small area and ought to be 
one of the doomed ; why is it common ? What, on Mr. Ridley’s views, 
settles the fate of a species in a country ? 
The hypothesis of youth (within the country) and area can only 
be accepted if one be prepared to accept with it the numerous absurdities to 
which it leads. It is very far-fetched, with no facts to rest upon, and 
involves a most remarkable amount of rising and falling in the scale 
of commonness (area of distribution) for which we have no warrant. In fact, 
it seems to me to require direction of evolution from outside, and in a very 
remarkable manner. A forthcoming paper, dealing with the distribution 
of the plants of the outlying islands of New Zealand, seems to me to finally 
decide the question against it. 
Mr. Ridley goes on to state that the endemics must be old, because 
there is nothing in the land from which they could have been evolved. 
This is a most remarkable statement, when one remembers that most of 
them have ‘ wides ’ in the same genus. He accuses me of omitting from 
a list of genera, definitely described as] containing five or more endemic 
species, the monotypic endemic genera, which he will find given in de- 
tail in Table XVII of my earlier paper (5). He states that most of these 
are rare, but if he will look at the figures he will find that they are RR, 
RC, C, RR, C, C, R, RC, VR, R, R, VR, RC, RR, RC, RC, RC, giving a 
rarity of 3-7, or considerably less than the endemics as a whole, and much 
below the rarity of the endemic genera with more than one species, which is 
4-2 for those with two or three, 4 -6 for Doona with eleven, and 5*4 for Stemo - 
noporus with fifteen. The rarity of the endemic genera goes in the opposite 
direction to that which one would expect were they being killed out. Why 
should genera with many species be nearer extinction than those with one, 
and the nearer the more species they have ? 
Mr. Ridley also states that I do not mention the fact that there 
are many genera which contain only endemic species. These he will 
find given in detail in Table XXV of the same paper (5). Adding 
these up, he will find that they only total 169, out of the 809 Ceylon 
