GREGORY: FISH SKULLS 



197 



(that probably housed a lateral branch of the air-bladder) formed by the transverse process 

 of the so-called fourth vertebra. The very small opercular still overlaps the anterior 

 border of the reduced ascending limb of the cleithrum. The preopercular is reduced 

 laterally to an oblique splint but it extends inward under the adductor muscles and con- 



Veri7,trpr 

 Veri6,trpr' 



wrfStrpr,^ 



vert^ trpr ., 

 {post, diir) 



fripusfcrcscprp 



vert^ irpr- 

 (antdiv) 

 tripus(antDrp 



vert 8 centrum 



Arius 



Fig. 79. Arius sp. "Crucifix" fish. 



tinues to form a significant lateral brace of the suspensorium. The very broad hyoman- 

 dibular is covered postero-laterally by the expanded supratemporal, which has largely 

 usurped the place and appearance of an opercular. The row of fused anterior vertebrae is 

 fully incorporated with the occiput, so that the tunnel-like transverse processes of the fourth 

 vertebra already mentioned appear to spring from the sides of the occiput, like the paroc- 



