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will ever stand supreme. This marvellous animal had the spinal 
column of a fish, the skull and jaws of a crocodile, the sclerotic 
plates of the eye resembling a like structure in turtles, lizards, 
and birds; it had the paddles of a whale articulated to the 
scapular arch of the Ornithorhyncus. Whence did this crea- 
ture trace its descent? What ancestors had it in the Triassic 
seas? But the rocks have not yet revealed from whence these 
complex structures were derived. Take again the Plesiosawrus, 
with its long neck united to the trunk of an ordinary quadruped, 
with the ribs of the chameleon, and the paddles of the whale. 
Several species are known, and their anatomy well understood. 
There is another type of skeleton which makes its first 
appearance with the dawn of the Lias age; it has a history 
quite unique, and its skeleton such as is found in no other 
reptile, living or extinct. The Pterodactyles present us with 
an assemblage of structural characters especially adapted to an 
aerial life. They have some resemblance to birds and bats, but 
they differ from both. From birds they are distinguished by 
the form of their vertebral column, and by the presence of 
teeth set in sockets; from mammals, by their conical teeth, 
small brain case, and reptilian structure of the shoulder joint. 
The wings of these flying reptiles were constructed on 
mechanical principles different from the wings of bats or birds. 
In birds the fingers are united, and serve for the support of the 
wing pinions: in bats the thumb is rudimentary, and the joints 
of the four fingers are elongated, to sustain the membrane that 
serves the purpose of a wing. On the contrary, the hand of 
the Pterodactyle resembles that of a lizard, the thumb and three 
fingers retain their normal size, but the little finger has all its 
joints strengthened and elongated, to form a rod for supporting 
a wing. Their long bones are hollow, and are traversed by 
air tubes like those of birds, and the carpal and metacarpal 
bones of the hand gave to these animals the delicate power of 
feathering the wing, either in air or water, in a way similar to 
the webbed feet of the Gannet and other diving palmipeds. 
The first Pterodactyle appeared in the Lias age, under the form 
of the Dimorphodon macronyzx, discovered in the Lower Lias of 
