254 Dr. R. H. Traquair — On Chondrosteus acipenseroides. 



the maxilla of its own side for tlie anterior half of its length, behind 

 which the margin recedes inwards, the little bone pt. being placed 

 just where the recession takes place. These plates were recognized 

 by Sir Philip Egerton as " palatine," and are undoubtedly the repre- 

 sentatives of the two plates occupying a corresponding position in 



Acipenser, and which, although formerly usually reckoned as " pala- 

 tines," are designated as " pterygoids " by Prof. W. K. Parker.^ To 

 my mind it seems to correspond more with the mesopterygoid of other 

 fishes, and I have lettered it accordingly. 



Placed at the middle of the outer edge of this last described bone, 

 and articulating both with it and with the maxilla, is a small 



1 Op. cii. p. 172. 



