128 LOUIS DOLLO. — SUR LA PHYLOGÉNIE DES DIPNEUSTES 29 JAN 



autostylic condition arises comparatively late in development, and never attains that 

 completeness which a Dipnoan ancestry would imply. 



In short, I would prefer to trace the origin of both Dipnoi and Urodeles from a 

 crossopterygian ganoid ancestry, the former being the apex of their line of develop - 

 ment, the latter tracing their descent through the Stegocephali. » 



[J. S. Ktsgsley. The Head of an Embryo Amphiwna. American Naturaust, 

 1892, p. Ô79). 



(122; MM. Boas, Cope et Kingsley admettent implicitement, ici, l'irréversibilité > 

 de l'évolution : autrement, ils seraient d'avis que — les dents, le prémaxillaire et le 

 susmaxillaire perdus pourraient se retrouver, — et que l'autostylie pourrait retour- 

 nera une phase moins parfaite. 



En quoi, je le répète, je suis tout à fait d'accord avec les naturalistes prémen- 

 tionnés. 



(1 23) E. D. Cope On the Phylogeny , etc., p. 280. 

 — H, B. Pollard. Polypterus, etc. 



« Polypterus is fitted to be the ancestor of Amphibia in so far its teeth are simple 

 but allied Crossopterygidae possessed Labyrinthodont teeth . » p. 421. 



« ... Polypterus which I take to represent fairly well the ancestor ofthe Stego- 

 cephali... )) p. 421 . 



«... On comparing the primordial cranium of a young Polypterus with that of 

 Urodeles the gênerai resemblance is seen to be so great that an anatomist seeing 

 alone for the first time would certainly place it among the latter. » p. 404. 



