352 Willis , — The Sources and Distribution of the 
(6) The maximum of the wides coincides with that of the endemics, 
and both decrease together from that point, the endemics much the more 
rapidly. 
(7) The specialized (later) and highly modified genera of Podoste- 
maceae and Tristichaceae are all strictly localized ; those that resemble 
ordinary water plants are widely scattered, and are just as common every¬ 
where. 
To these one may add the following notes and queries, which if not 
successfully answered, are very fatal to the view that endemics are chiefly 
relicts: 
(a) How, on the view that endemics are relicts, is it possible success¬ 
fully to predict what has already been successfully predicted by the aid of 
age and area ? 
(b) How are the facts of the regular graduation of species, of narrowly 
localized endemics up, and of wides down, to be explained at all ? 
(c) Why is there no difference in behaviour between endemic genera 
and species ? 
(^)~Why does a genus behave in just the same way in New Zealand 
(for example), whether endemic with small area, endemic with large, endemic 
in New Zealand, endemic in New Zealand and islands, endemic in New 
Zealand and Australia, or endemic in New Zealand and the rest of the 
world ? 
(e) Why do all endemics show graduated maps like those given 
above ? 
(/) Why are the endemics of the same order of rarity in all families 
and genera ? 
(g) Why are the endemics of the same order of rarity whether there 
are or are not wides in the same genera ? 
(h) Why is an endemic genus the rarer the more species it has ( 17 , 
p- 323) ? 
( i) Why should the islands round New Zealand have more endemics 
the more wides they have (21, p. 332) ? 
( k ) Why are the endemics of New Zealand least numerous at the 
ends of the islands and not in the middle, and the wides the same (20, 
p. 201)? 
(/) Why do the endemics that reach the ends of New Zealand range on 
the average so much farther than those in the middle ( 19 , p. 448) ? 
(m) Why are the endemics still less numerous in proportion on the 
islands surrounding New Zealand than on New Zealand itself, and the 
wides more numerous? (N.Z. Wides/Endemics 301/902, Kermadecs 45/25, 
Chathams 69/76, Aucklands 27/72). 
(«) Why do the endemics of both northern and southern invasions (cf. 
this paper, below) taper down in number with the wides, but much more 
