The Chain of Life in Geological Time: A Sketch of the Origin and Succession of Animals and PlantsDawson, John William, Sir
Science
The Chain of Life in Geological Time: A Sketch of the Origin and Succession of Animals and Plants
Dawson, John William, Sir
Paleobotany; Paleontology
The approximation of the winged reptiles to the birds is further
increased by the facts that in the Jurassic and Cretaceous periods there
were birds having reptilian tails and probably toothed jaws
(_Archæopteryx macroura_, Fig. 148). The species just named, while in
its limbs, trunk, and feathers a veritable perching bird, resembles a
reptile in its head and tail. In the Cretaceous of Western America,
Marsh has recently discovered two distinct types of toothed birds, one
having the teeth in regular sockets, the other having them implanted in
a groove in the jaw. One of these birds (_Ichthyornis dispar_, Fig. 149)
was larger than a pigeon, with powerful wings constructed like those of
ordinary birds. It had also the curious and old-fashioned peculiarity of
biconcave vertebræ, like those of fishes and some reptiles. Another
(_Hesperornis regalis_) stood five or six feet high, and had rudimentary
wings like those of the Penguins. These toothed birds extend into the
Eocene Tertiary, where the _Odontopteryx_ of Owen has been known for
some time. In the Eocene, however, this toothed bird is associated with
others of ordinary types, allied closely to the Ostriches, the Pelicans,
the Ibis, the Woodpeckers, the Hawks, the Owls, the Vultures, and the
ordinary perching birds. In the Later Mesozoic, indeed, some reptiles
became so bird-like that they nearly approached the earliest birds; but
this was a final and futile effort of the reptile to obtain in the air
that supremacy which it had long enjoyed in earth and water; and its
failure was immediately succeeded in the Eocene by the appearance of a
cloud of true birds, representing all the existing orders of the class.
[Illustration: FIG. 150.—Jaw of _Bathygnathus borealis_ (Leidy). A
Triassic Dinosaur from Prince Edward Island.
_a_, Cross section of second tooth, natural size. _b_, Fifth tooth,
natural size.]
We may close our notice of the winged reptiles of the Mesozoic by
quoting from Phillips his summary of the characters of _Rhamphorhyncus_
(Fig. 147)[67]: “Gifted with ample means of flight, able at least to
perch on rocks and scuffle along the shore, perhaps competent to dive,
though not so well as a palmiped bird, many fishes must have yielded to
the cruel beak and sharp teeth of the _Rhamphorhyncus_. If we ask to which
of the many families of birds the analogy of structure and probable way
of life would lead us to assimilate _Rhamphorhyncus_, the answer must
point to the swimming races, with long wings, clawed feet, hooked beak,
and habits of violence and voracity; and for preference, the shortness
of the legs and other circumstances may be held to claim for the
Stonesfield fossil a more than fanciful similitude to the groups of
Cormorants and other marine divers which constitute an effective part of
the picturesque army of robbers of the sea.”
[Illustration: FIG. 151.—_Hadrosaurus Foulkii_ (Cope). An Herbivorous
Dinosaur, 28 feet long.—After Hawkins’s restoration.]
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