204 A. G. HAMILTON. 
and they would to some extent drop out of the race. Again, the 
surface disturbances would destroy other insects and the same 
would occur here, while on the other hand, the accumulation of 
dead timber would favour wood-boring insects and these if special- 
ised to fertilise any particular plants, would give an advantage to 
those plants in competition with others not so favoured. It is 
easy to see then, how destruction of forest and other flora might 
react on the native fauna, and cause scarcity or extinction, or 
increase to a large extent in various groups of the animal kingdom, 
and this increase or extinction would have a very important effect 
on the flora. 
Division II. 
Introduction of a new fauna altering the flora; and the destruction 
of the native fauna modifying it. 
This may be divided into two subdivisions: first, The introduc- 
tion of a new fauna, and second the destruction of the native 
fauna—altering indigenous vegetation. These may be examined 
under the following heads :— 
First Subdivision— 
(a) Direct destruction of flora caused by introduced fauna. 
(6) Alteration of drainage caused by introduced fauna. 
(c) Alteration of soil caused by introduced fauna. 
(ad) Spreading new plants by introduced fauna, 
Second Subdivision— 
(a) Direct destruction of native fauna and its effects on plants. 
(6) Indirect modification of native fauna and its effects. 
First Subdivision—ZJntroduction of a new fauna. 
The introduced fauna is fairly large and comprises animals of 
many natural orders. The vertebrates comprise dogs, foxes, cats, 
rabbits, hares, rats, mice, cows, buffaloes, sheep, goats, deer, camels, 
swine, horses, birds, particularly the domestic fowls, pigeons and 
sparrows. Among the invertebrates are planarian worms, earth- 
worms, various ento- and ecto-parasites, insects and mollusca. 
Sn 
. 
OO a ae ae 
