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When the general results of the restoration of extinct species and their relations to 
existing species of the different continents and islands of the globe are first received, they 
commonly suggest the idea that the races of animals have deteriorated in respect of size. 
The more striking phenomena first and most strongly impress the mind, which contrasts, 
for example, the great Cave-Bears of Europe with the actual Brown Bear, the Megathe- 
rioids of South America with the small existing Sloths, and the gigantic Glyptodons with 
the Armadillos. The huge Diprotodon and Nototherium suggest a similar contrast with 
the Kangaroos of Australia; and the towering Dinornis and Palapteryx with the humble 
Apteryx of New Zealand. But the comparatively diminutive animals of South America, 
Australia and New Zealand, that form the nearest allies of the gigantic extinct species 
respectively characteristic of such tracts of dry land, are yet specifically if not generi- 
cally distinct from them, nor have such small species been more recently introduced. 
In England, for example, our Moles, Water-voles, Hares, Weasels, Stoats, Badgers and 
Foxes are of the same species as those that existed when the Hippopotamus swam the 
rivers, the Hyzna, Bear and Lion lurked in the caves, and the Rhinoceros and Elephant 
trod the land. So likewise the remains of small Sloths and Armadillos are found asso- 
ciated with the Megatherium and Glyptodon in South America; and the fossil remains 
of species as diminutive as the present Kangaroos and Dasyures occur abundantly in 
Australia with those of herbivorous Marsupials as large as Tapirs and Rhinoceroses, and 
of carnivorous Marsupials as large as the Lion or Tiger. So likewise in New Zealand 
we find that the small Apterya and Notornis have co-existed with the great Dinornis and 
Palapteryx. 
We have not a particle of evidence that any species of bird or beast that lived during 
the pliocene period has had its characters modified in any respect by the influence of time 
or of change of external influences. In proportion to its bulk is the difficulty of the 
contest which, as a living organized whole, the individual of such species has to 
maintain against the surrounding agencies that are ever tending to dissolve the vital 
bond, and subjugate the living matter to the ordinary chemical and physical forces. 
Any changes, therefore, in such external conditions as a species may have been originally 
adapted to exist in, will militate against that existence in a degree proportionate, per- 
haps in a geometrical ratio, to the bulk of the species. Ifa dry season be gradually 
prolonged, the large Mammal will suffer from the drought sooner than the small one: 
if any alteration of climate affect the quantity of vegetable food, the bulky Herbivore 
will first feel the effects of stinted nourishment: if new enemies are introduced, the 
large and conspicuous quadruped or bird will fall a prey, whilst the smaller species 
conceal themselves and escape. Smaller animals, also, are usually more prolific than 
larger ones. 
The actual presence, therefore, of small species of animals in countries where larger 
species of the same natural families formerly existed, is not the consequence of any 
gradual diminution of the size of such species, but is the result of circumstances, 
which may be illustrated by the fable of the ‘oak and the reed’: the smaller and feebler 


