464: F. VON HUENE DEVELOPMENT OF THE ICHTHYOPTERYGIA 



are^, it appears to me, a primitive short side branch of the theoretic main 

 line leading to the ichthyosaurs. 



This primitive gronp^, which has not yet been found in the Permian, 

 but which certainly existed in that epoch, mnst have been a parallel 

 branch with the Cotylosauria, both having sprung from the Carboniferous 

 Embolomeri. The evidence for this is given in detail in the paper cited 

 above. 



r « .. 



Figure 1. — Xeic Restoration of the Skull of Mcsosaunis hraziliensis from the Permian 



of Irah, Brazil 



Natural size. From specimens at the Fniversity of Tiibingen. 



Eo :=: Basioccipitale. 



Bs = Basisplienoid. 



Jug = Jugale. 



Mx = Maxilla. 



X =: Nasale. 



No = Internal nares. 



Pal = Palatinum. 

 Pm = Prsemaxilla. 

 Pt = Pterygoid. 

 Q = Quadratum. 

 Vom = Vomer. 



Omphalosaurus 



Omphalosaunis is a coastal remnant of rather primitive Ichthyosauria, 

 which have not yet become so well adapted to marine habits as have later 

 forms. Both Mesosauria and Omphalosauria exhibit marked evidence of 

 pachyostosis, according to Nopsca/ and are therefore on the way toward 

 aquatic adaptation. 



* Anatom, Anzeiger, 1922 ; Pala^ont. Zeitsclir., v, 3, 1922. Both papers are still in 

 press. 



