144 THE TRANSFORMATIONS OF THE ANIMAL WORLD 



The facts above mentioned all apply to variations 

 of a fossil type in the same deposit or in neighbour- 

 ing beds, that is to say, what we have termed varie- 

 ties. But would it be possible to detect in early 

 times variations of a geographical order, repro- 

 ducing the local races so frequent among living 

 species ? The attention of palaeontologists does 

 not appear, till now, to have been much drawn 

 to this point. A learned French geologist, J. 

 Bergeron, who has discovered and made known 

 the earliest fossil fauna in our country, that of the 

 Cambrian soil of the Montagne Noire, has noticed 

 that the Trilobites of this southern district belonged 

 to species almost identical with those of the Bo- 

 hemian Cambrian, but showing certain constant 

 differences in the details of the ornamentation 

 of the chitinous test. In the same way the 

 Conocorypha coronata of Languedoc and Spain 

 differs from the typical species of Bohemia by the 

 presence of a spike instead of a tubercule on the 

 occipital ring and by a coarser granulation of the 

 whole surface of the head. The Paradoxides 

 rugulosus is, in its turn, not quite identical with that 

 of Bohemia, for it exhibits no tubercule on the 

 occipital ring. With a reserve which should find 

 many imitators, Bergeron did not deem it needful 

 to separate these southern forms under a new 

 specific name, the least inconvenience of which 

 would have been the concealment of the natural 

 affinities of the species of Trilobites of these two 

 distant regions. 



In Secondary times, there may be quoted, as a 

 good example of regional variation, the two forms 



