wide difference
between the pig and the camel. ↑5 blocks not present in 1859 1860 1861 1866 1869; present in 1872 | The Ungulata or hoofed quadrupeds are now divided into the even-toed or odd-toed divisions; but the Macrauchenia of S. America connects to a certain extent these two grand divisions.
No one will deny that the Hipparion is intermediate between the existing horse and certain older ungulate forms.
What a wonderful connecting link in the chain of mammals is the Typotherium from S. America, as the name given to it by Professor Gervais expresses, and which cannot be placed in any existing order.
The Sirenia form a very distinct group of mammals, and one of the most remarkable peculiarities in the existing dugong and lamentin is the entire absence of hind limbs, without even a rudiment being left; but the extinct Halitherium had, according to Professor Flower, an ossified thigh-bone "articulated to a well-defined acetabulum in the pelvis," and it thus makes some approach to ordinary hoofed quadrupeds, to which the Sirenia are in other respects allied.
The cetaceans or whales are widely different from all other mammals, but the tertiary Zeuglodon and Squalodon, which have been placed by some naturalists in an order by themselves, are considered by Professor Huxley to be undoubtedly cetaceans, "and to constitute connecting links with the aquatic carnivora."
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↑1 blocks not present in 1859 1860 1861 1866; present in 1869 1872 | Another distinguished palæontologist, M. Gaudry, shows that very
many of the fossil mammals discovered by him in Attica connect in the plainest manner
existing genera.
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In regard to the Invertebrata, Barrande, and a higher authority could not be named, asserts that he is every day taught that
palæozoic animals, though belonging to the same orders, families, or genera with those living at the present day,
were not at this early epoch limited in such distinct groups
as they now
are.
↑2 blocks not present in 1859 1860 1861 1866 1869; present in 1872 | Even the wide interval between birds and reptiles has been shown by the naturalist just quoted to be partially bridged over in the most unexpected manner, on the one hand, by the ostrich and extinct Archeopteryx, and on the other hand, by the Compsognathus, one of the Dinosaurians— that group which includes the most gigantic of all terrestrial reptiles.
Turning to the Invertebrata, Barrande asserts, and a higher authority could not be named, that he is every day taught that, although palæozoic animals can certainly be classed under existing groups, yet that at this ancient period the groups were not so distinctly separated from each other as they now are.
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Some writers have objected to any extinct species
or group of species
being considered as intermediate between living
species
or groups. If by this term it is meant that an extinct form is directly intermediate in all its characters between two living forms,
the
objection is
....... 1861 1866 1869 | probably 1859 1860 1872 |
valid. But I apprehend that
in a perfectly
natural classification many fossil species would have to
stand between living species, and some extinct genera between living genera, even between genera belonging to distinct families. The most common case, especially with respect to very distinct groups, such as fish and reptiles, seems to be, that
supposing them to be distinguished at the present day from each other
by a dozen
characters, the ancient members of the same two groups would be distinguished
by a somewhat lesser number of characters,
so that the two groups,
though
formerly quite distinct, at that period made some small
approach to each other.
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