958 Marvels of the Untverse 
A LIVING GORDIAN KNOT. 
A soft black Worm without external organs of any kind, and of extraordinary length. As commonly seen, coiled up in some 
empty shell its principal occupation appears to be tying itself into a hopeless tangle—trom which, however, it glides with 
absolute ease. 
million years ago. He has chosen the period known as ‘“‘the Age of Reptiles,’’ when these 
creatures were the dominant types of life on the earth, and when the Mammals, which trace 
their descent from the Reptiles, were just appearing. 
The most striking figure in his picture is naturally the flying dragon, or Pterodactyl, Dimor- 
phodon, which was undoubtedly a carnivorous creature. It has been suggested that it was also 
warm-blooded, which is quite possible, though, this being the case, it differed from all other 
reptiles, which are a cold-blooded race. The Dimorphodon is depicted as about to wrest a meal 
from the jaws of one of the ancient crocodiles, evidently a near ally of the marine armoured 
crocodile Teleosaurus, a type bearing a strong resemblance to the long-snouted Gavials of to-day. 
And what about the “ meal,” the subject of the dispute. Here was a difficulty. It is certain 
that the day of the mammals had begun at the time these reptiles were living, for the records of 
the rocks proclaim as much, though only by fragments too imperfect to enable us to reconstruct a 
convincing picture. Accordingly the most primitive of living mammals to-day, the Duck-billed 
Platypus, or Ornithorhynchus, has been chosen to represent these ancient prototypes. The Duck- 
bill is well-named paradoxus, for while it is undoubtedly primitive, retaining many characters 
derived from its reptilian forbears, in others, as in the duck-like beak, it is highly specialized. 
Among its primitive characters the most striking, of course, is the fact that it lays eggs, a peculiarity 
shared only by the Echidna, among mammals, and there can be no doubt but that the early 
mammals were oviparous, as the reptiles remain to this day. 
In his handling of the Pterodactyl Mr. Whymper has shown great restraint—at any rate, in 
so far as coloration is concerned; for it is quite probable that these agile creatures displayed 
vivid and rapidly changing hues, as is the case with many reptiles to-day, even among quite 
sluggish species. 
