SKULL 



237 



It is in the connection of the skull with the visceral arches 

 the Dipnoi have diverged most conspicuously from other fish. 



k 



that 

 The 



II -IP 



T3 E 2 3 



I&J.S-J3 



2 o 3 t. s 3 

 S-.-n-g.3S 

 8 fll^ 



lslli.5 



modern genera are completely autostylic (p. 95). The ptery go- 

 quadrate bar is firmly fused to the cranium in front and behind. 

 The spiracle disappears ; and the hyoid arch is well developed, with 

 i\ median basihyal, paired hypohyals, and large ossified ceratohyals 



