GENERIC TYPES. 51 



3. The 12 primitive types show, in their earliest species, the 

 contrast and plentitude of their characters. 



This plentitude and this contrast are above all remarkable 

 in two straight types : Orthoceras and Bathmoceras. One 

 sees also in some species the maximum of size known, as in 

 Naut.ferox Bill, of Canada. The plentitude of typical char- 

 acters and the size not surpassed by later appearing species, 

 are in disaccord ance with the slow and successive progress 

 attributed to evolution. 



4. The 12 primitive types are very unequally distributed in the 

 palaeozoic countries. This distribution indicates no centre 

 of diffusion, no point of departure for evolution. 



5. Among the 12 primitive types, are found those the most con- 

 trasted in form and structure. Ex. : 



Orthoceras, with straight shell. 



Cyrtoceras, with curved shell. 



Nautilus, completely spiral in the same plane. 



Trochoceras, doubly spiral. 



Bathmoceras, shell straight, but characterized by an obso- 

 lete siphon. 



In order to derive from a common ancestor types so much 

 differentiated, one must have an indefinite number of genera- 

 tions and of transition-forms, of which there remain no I face 

 whatever. 



6. The 14 types posterior to the 12 primitive types, also appeared 

 as suddenly, without being announced by any transition-form, 

 as for example: Ascoceras and Goniatites. One can apply 

 to them also the preceding observation. 



7. The vertical position of the 20 types in respect to their first 

 appearance, otters a combination the most opposed to evolu- 

 tion, for instead of showing a successive progress in the 

 number of first appearances, it presents a rapid diminution 

 thereof. In fact : 



16 of these 26 first appearances (comprising the 12 primi- 

 tive types) are found within the limits of the 2d fauna. 

 8 in the limits of the 3d fauna. 

 1 towards the end of the Devonian fauna. 

 1 during the Eocene period. 



