Australasian Fossils: A Students' Manual of PalaeontologyChapman, Frederick
Science
Australasian Fossils: A Students' Manual of Palaeontology
Chapman, Frederick
Paleontology -- Australia
Other, somewhat doubtful remains having similar affinities to the
labyrinthodonts are also recorded from the Wianamatta beds (Upper Trias)
at Bowral, New South Wales, consisting of a maxilla with teeth and 11
vertebrae with ribs of the left side. Remains of a labyrinthodont,
_Biloela_, supposed to be related to _Mastodonsaurus_, have been
recorded from the Hawkesbury Series of Cockatoo Island, Port Jackson,
New South Wales, by W. J. Stephens, and consisting of a pectoral plate
compared by that author with _M. robustus_ (now transferred to the genus
_Capitosaurus_).
The only other recorded remains of this group in Australasia are those
noted by W. J. Stephens from the Kaihiku Series (Trias) at Nugget Point,
Otago; and in the Otapiri Series (Upper Trias) of the Wairoa district, New
Zealand.
=Reptilia: Their Structure.--=
_REPTILIA._--The Reptiles are cold-blooded, vertebrated animals, with
a scaly skin or armour. Their respiration is essentially by means of
lungs, and they are terrestrial or aquatic in habit. The skeleton is
completely ossified (bony). Reptiles, although resembling amphibians
externally, are more differentiated in structure and of generally
larger proportions. They exhibit great diversity of form, especially as
regards their extremities. They were even adapted for flying, as in
the Pterosaurs ("Flying Dragons") with their membranous wing attached
to the anterior limb. The Deinosaurs ("Terrible Reptiles") were often
of great size, exceeding the dimensions of any land mammals, and their
limbs were adapted for walking. The marine reptiles, as the Ichthyosauria
("Fish-lizards") and Sauropterygia ("lizard-finned") had the limbs
transformed into paddles. The neural spines in the vertebra of the Turtles
are laterally expanded into a carapace and united with dermal plates.
The vertebrae of Reptilia show great variation of form, being biplanate
(amphiplatyan), biconcave (amphicoelus), hollow in front (procoelus),
or hollow at the back (opisthocoelus). In the case of Reptiles having
both pairs of limbs developed, the cervical, dorsal, sacral and caudal
regions may be separately distinguished. Amongst the Ophidia (Snakes),
Pythonomorpha ("Sea-lizards") and Ichthyosaurs ("Fish-lizards") there is
no differentiated sacral region. The skull of the Reptiles is nearer that
of Birds than Amphibians. The basiocciput (basal bone of the skull at the
back) articulates with the atlas (top joint of the backbone) by means of
a single condyle (protuberance). All reptiles, with the exception of the
Chelonians (Turtles), and a few others, are furnished with teeth: these
are formed chiefly of dentine with a layer of enamel.
=Dentition.--=
Some teeth have solid crowns (pleodont); some grow from persistent pulps
(coelodont); socketed teeth (thecodont) are inserted in alveoli; some are
fused with the supporting bone along the outer rim or top (acrodont);
whilst others are developed laterally along the flange-like inner rim of
the jaw (pleurodont).
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