L000 Marvels of the Universe 
PARIASAURUS, AN ANCIENT 
RISE TUL, 
BY R. I. POCOCK, BRS: 
TIME was, and that not so very long ago, when zoo- 
logists thought they had sufficient evidence to justify 
the theory that the mammalia were descended directly 
from the class of vertebrata to which the toads and 
salamanders belong, and that the reptiles, which were 
guessed to be the progenitors of the birds, occupied a 
side branch of the tree of life. It is now, however, 
believed that the characters mammals have in com- 
mon with salamanders have been transmitted to the 
former through a group of reptiles, now wholly 
extinct, which, from its many mammalian features, is 
commonly called the Theromorpha. 
7 : One of the best-known of these is Pariasaurus, 
a nearly complete skeleton of which is mounted in 
the Natural History Museum at South Kensington. 
Photo by] (H. Main. ‘i 4 o - 
THE CHRYSALIS. Although only a few feet high and some eight o1 
The Maggot contracts and its skin hardens. nine feet long, Pariasaurus was evidently a beast of 
Within the pupa or chrysalis has formed. 
great strength and weight ; and the general massive- 
ness of its build and its short, but powerful limbs suggest anything but agility of movement, 
while the shortness of the tail coupled with the structure of the feet leaves little doubt that it 
was purely terrestrial, and neither aquatic nor arboreal in habits. That its food was vegetable is 
indicated by the shape and setting of its teeth; and that the plants it fed on were tough and 
fibrous may be inferred from the stoutness of its jaws. 
Pariasaurus lived during Triassic times, and is one of the most ancient reptiles yet discovered. 
The interest of this circumstance is increased by the many points of resemblance it shows to certain 
great creatures, the Labyrinthodons, which are still older, and which are not true reptiles at all, 
but belong to the class Amphibia, which comprises the frogs, toads, salamanders and newts of the 
present day. Pariasaurus, therefore, is, in a measure, an annectant type, serving to bridge the passage 
between these two great classes of cold-blooded vertebrates. On the other hand, as has already 
been said, it indicates the line of descent of the mammals. It must not be supposed, however, 
that it was the ancestral stock of our own class. This distinction must be assigned rather to another 
group of reptiles, related, but not very closely related, to Pariasaurus, but of the same age and 
horizon. 
These are the Cynodontia, or dog-toothed reptiles, which had tearing teeth of a highly- 
perfected, predatory type; and the reason for mentioning them in this connection is the certainty 
that they were the only living enemies that Pariasaurus and its allies had to fear. In those ancient 
days, indeed, these two groups of reptiles fulfilled the role that is now played by carnivorous and 
herbivorous mammals, thus attesting the fierceness of the struggle for existence in the dim dawn 
of vertebrate evolution. 
Another interesting point about this great reptile is the wonderful extent of its longitudinal— 
that is to say, of its north and south—distribution in the world. It was first discovered in Cape 
Colony ; but since then its remains have been unearthed in abundance in the valley of the Dwina, 
close to the shores of the White Sea. Now if Pariasaurus were a mammal, we should have no right 
to assume that its occurrence in such widely-sundered localities proved identity, or even close 
