Manchester Memoirs, Vol. Ivii. (191 2), No. 



dentary meeting the angular. The combined prearticular 

 and coronoid is a very large bone running from the 

 extreme back of the jaw far forward to near the splenial 

 -symphysis ; towards the front it widens and reaches down 

 nearly to the lower border of the jaw, bordering the 

 tooth-bearing border of the dentary above. 



The small bone which in Stegocephalia is usually 

 called the coronoid, but which I have endeavoured to 



t-?XTs. 



A. Left raimis of lower jaw of '* I .oxovimn.^ 



. aspect. 



B. Right ramus of the same jaw. Outer aspect. x \. 

 Ano;, Angular. Cr., Coronoid. Den., Dentary. 



Ep.Cr., Kpicoronoid. Pr.Art., Pre-articular. 

 Sr., Splenial. Sitr.Ang., Surangular. 



shew is not homologous with the reptilian bone of that 

 name, and called the Epicoronoid, lies entirely on the 

 inner side of the jaw. It articulates with the dentary 

 above, running along its inner edge for some distance, its 

 lower border being overlapped by the prearticular. The 

 jaw as a whole is of very ordinary type, differing from 

 the majority of Stegocephalian jaws in lacking the internal 

 mandibular vacuity,and being veryprimitive in the fact that 



