PLATE VI. 



Fia. 19. The palatopterygoidean arcade of Amia calva, together with other associated 

 bones and the hyoidean arch, to the outer side of which articulate the 

 twelve branchiostegal rays, Brs. B. The dotted portions about the hypo- 

 hyal, metapterygoid and epihyal represent cartilage, but all other cartila- 

 ginous and membranous portions have been carefully removed. This figure 

 well shows the relation of the hyoidean arch to the other bones represented, 

 as it does the position occupied by the semi-anchylosed preoperculum. 

 Life size fi-om nature, by the author. 



106 



852 



