386 Dr. A. Smith Woodward— Notes on Pycnodont Fishes. 



beneath the antero-dorsal scales, and may perhaps be regarded as the 

 post-temporal. It is, at any rate, noteworthy that in Gyrodus, where 

 separate supratemporals and post-temporals appear to be recogniz- 

 able 1 the parietal is exceptional in lacking the small posterior process. 

 The otic region is completely covered by a squamosal plate (*<?.). 



Mesodon macropterus (Agassiz) ; restoration, with cheek-plates removed, 

 about two-thirds nat. size. Upper Jurassic (Lithographic Stone) : 

 Bavaria. Jr. frontal ; m.eth. mesethmoid ; md. mandible, showing 

 narrow dentary in front; op. operculum; orb. orbit; p. op. pre- 

 operculum ; pa. parietal ; pas. parasphenoid ; pmx. premaxilla ; s.occ 

 supraoccipital ; sq. squamosal ; v. vomer. Drawn by Miss Gertrude 

 M: Woodward, chiefly from a specimen in the British Museum 

 (No. P. 5546). 



The frontals (fr.), which meet in a median suture, are the largest 

 bones of the roof, sometimes ending abruptly just in advance of the 

 orbit, sometimes tapering along the upper edge of the mesethmoid 

 element of the snout. 



1 E. Hennig, Pakeontographica, vol. liii (1906), p. 143, pis. x, xi. 



