458 MR. U. BROOM ON THE TERSISTENCE OF THE 



name should be treated as a nome)i iiiodnvi. Conodecies has eight 

 years' priority over Seynwuria, and if those wlio have examined 

 both types are satisfied that they belong to the same species, 

 I think we will have to use Cope's name Concdectes favosus in 

 preference to that of Brioli. 



The second point is a much more debatable one. Watson 

 describes " »S'e?/?>i.o?tria " as " the most primitive known reptile," 

 and everyone else who has written about the animal has also 

 been of the opinion that it is a reptile ; and until Watson's paper 

 appeared, I also accepted this opinion, having never seen any of 

 the actual specimens. I do not in the present paper wish to enter 

 at length into the discussion, but may state that the study of 

 Watson's paper leads me rather to the conclusion that Conodectes 

 is a highly evolved and specialized Embolomerous Amphibian, 

 with a very few reptile-like characters which have been acquired 

 by a parallel development. For the present, however, it matters 

 little whether Conodectes is an Amphibian-like Reptile or a Reptile- 

 like Amphibian. It certainly lets us know more of the primitive 

 Tetrapod structure than almost any othei; known type, and for- 

 tunately the palate is well known, and has been fully described 

 by Watson. 



There is a large pterygoid which meets its neighbour in front, 

 and it is supported indirectly by a basipterygoid process. Between 

 the process and the pterygoid is a distinct bony element, con- 

 cerning which Watson says : — "The short basipterygoid processes 

 of S'ei/mouria supporting the pterygoid through the intervention 

 of a special bone are unique, nothing similar occurring in any 

 other known adult reptile or amphibian. The shape and position 

 of the pterygoid render it certain that these special bones cannot 

 be the epipterygoids, which in Dimetrodon are known to articu- 

 late with the basisphenoid. Swinnei^ton and Howes showed that 

 in the development of the skull of Sphenodon special articular 

 cartilages are developed between the basipterygoid processes 

 and th.e pteiwgoid, and it is not impossible that these are the 

 representatives of the articular bones in Seymouria. 



•' On the other hand, Gaupp has shown that in Lacerta the 

 Imsipterygoid processes contain independent centres of ossification, 

 and it is feasible and attractive to regard the Seymcmria bones as 

 permanently separate autogenous basipterygoid processes." 



With regard to this second suggestion, it may be mentioned 

 that the basisphenoid in lizards and many other animals ossifies 

 for the most part from the parasphenoid, and, so far as I am 

 awai'e, no one has confirmed Gaupp's observation. Parker 

 examined an embryo Zootoca (his 6th stage) which one would 

 fancy ought to show the basipterygoid distinct if it is ossified 

 from a separate centre ; but there is no evidence of this. Howes 

 and Swinnerton figui-e a stage in the development of the skull of 

 Sphenodon (stage 8) where the basisphenoid is evidently ossified 

 from a pair of centres each of which embraces the basipterygoid 



