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Royal Institution of London. 
in the Old World mammals reached their highest type. Among 
other illustrations of this truth, he contrasted the lion and the 
royal tiger of Asia and Africa with the puma and jaguar of Ame¬ 
rica ; the large and useful camel with the feeble vicugna. The 
most remarkable of the herbivorous and pachydermatous animals, 
as the giraffe and the antelope in the former class, and the ele¬ 
phant, rhinoceros, hippopotamus, babroussa, horse, djiggitas, 
zebra in the latter, are peculiar to the Old World. With respect 
to the rodent animals, water-rats, hares, rabbits, tailless hares, 
are only found in the Old World. The beaver is, indeed, repre¬ 
sented by an American species, but this is distinct from the beaver 
of the Danube. The monkeys of the Old World are equally 
distinguishable from those of the New. In the latter we find the 
prehensile tail, the wide and approximated nostrils, and the 
absence of an opposable thumb on the hand. 
Prof. Owen proceeded, 2ndly, to notice the peculiarities of 
mammalian distribution in Australia and the neighbouring 
islands.— In this tract of the globe all the animals are distinguished 
by two remarkable peculiarities, one positive and the other nega¬ 
tive : (a) all are organized to carry about their young, from a 
very early period of embryonic life, in a portable pouch; and ( b) 
none have attained a high degree of development. The largest 
marsupial carnivora are the Thylacinus and Dasyurus, which are 
respectively of the size of the dog and the wild cat. 
3. Probable final causes of several instances of this develop¬ 
ment were then adverted to. Thus, the marsupial inhabits a 
country liable to long-continued drought, and where the indi¬ 
genous animals are consequently compelled to make long journeys 
in search of water; were it not for the arrangement enabling 
the marsupial to carry its young with ease from one place to 
another, the races would probably become soon extinct. The 
prehensile tail of the American marsupial, as well as of the por¬ 
cupine, kinkajous, ant-eaters and monkeys of the New World, 
have reference to their arboreal life in the huge forests in which 
these creatures live. Then, to prevent mischievous effects from 
the decomposition of vegetable matter in countries where it is so 
luxuriant, decaying plants furnish food to Termites and other 
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