GAUDRY AND EVOLUTION—GLANGEAUD. 423 
Arctocyon, it binds this family to that of the dogs, which to-day 
are quite distinct. Associated with animals half civets and half 
hyeenas one finds a true hyzna, intermediate between the common 
species now living in Africa, the spotted, and the striped hyenas.” 
(Gaudry. ) 
In comparing the fossils of Pikermi with those which one finds 
in more ancient formations, as for example those of Sansan (Gers) 
or Auvergne, similar relationships were discerned by Gaudry, and 
indicated to him that Pikermi is not the only deposit which presents 
intermediate types. 
“ He concludes that organic types are not distinct entities, but that 
they ally themselves on the one hand to the older types, which can be 
considered the ancestors of the former, and, on the other hand, with 
more recent types, which may be regarded as their descendants. 
The modifications which he discovers, in passing from a given form 
to a neighboring form, are so inconsiderable, the transformations are 
so closely coordinated with the time, that he is led logically to con- 
clude that the species of fossil animals are not immutable beings, but 
that they are transformed into others; that modification (changement) 
is the supreme law of the animal world as of the physical world.” 
(Boule. ) . 
Thus Gaudry gave to the theory of evolution a more solid basis, 
one which it lacked previously, the paleontological argument. And 
would it not be strange and unscientific not to take into account 
fossil animals, the species of which are so much more numerous than 
the living forms? 
The appearance of the great and remarkable work on “ The fossil 
animals and geology of Attica,’ in which Gaudry expounded his 
ideas on the fauna of this region, marked an important date in the 
history of paleontology and of the animal kingdom. The study of 
the fauna of Pikermi established the scientific reputation of the 
naturalist among scholars. 
2. Mount Léberon. Migrations. 
Some years later (in 1872) Gaudry undertook researches at Mount 
Léberon near Cucuron (Vaucluse) in a formation having very close 
analogies in age and faunas with Pikermi. He was led to study this 
formation “in order to discover whether not only the genera and 
families of mammals, but also the species, have been immutable 
entities, or whether they do not show sufficient plasticity to indicate 
that they are descended from one another.” 
The work on Léberon was done while that on Pikermi was in 
progress, and supplemented it in many points, 
45745°—sm 1909——28 
