Fig. 132—Bothriceps major,
A. S. Woodward.
Carbopermian. New South Wales.
About 1/11th. nat. size
(After A. S. Woodward).
Triassic Labyrinthodonts.—
From the Hawkesbury Series near Gosford, New South Wales, the labyrinthodont, Platyceps wilkinsoni has been described. The skeleton is nearly complete and exposed on the ventral face; the head is 27mm. long and 32mm. broad. This specimen is associated with the remains of ganoid fishes, as Palaeoniscus and Cleithrolepis, together with the equisetum-like plant Phyllotheca.
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.