PLATE III 

 THE STRUCTURE OF VARIOUS PARTS OF THE HEAD ROOF 



Fig. 3 Plaster cast of the post-nasal plate of Dinichthys (') intermedius Nwb. seen from the outside. 

 Fig. 4. The same viewed from the inside. 



SO, top of sub-orbital; ns, nasal impression. 



Fig. 5. Inside view of nearly complete sclerotic ring of Dinichthys sp. 

 American Museum of Natural History, No. 507lG. 



Fig. 6. Outside view of the post-nasal plate of Dinichthys terrelh Nwb. 

 ns, nostril impression; fito, process touching post-orbital plate. 



American Museum of Natural History, No. 3562. 

 Fig. 7. Left hind corner of the head roof of Dinichthys sp. 



M, marginal plate; PM, post -marginal plate; EB, corner of externo-basal plate. 



All figures in natural size. 



