PIETSCH: OSTEOLOGY AND RELATIONSHIPS OF TETRABRACHIUM 



Pterotic , 



Supraoccipital 



Posttemporal 



Vomer 



Uteral ethmoid 



Figure 17. — Dorsal view of cranium of Brachio 

 nichthys hirsutus, AMS IA.6064, 69 mm SL. 



Neut3l spine of 22nd 

 pre -oral centrum 



Epiotic 



Parietal 



Sphenotic 



Parietal , 



Supraethmoid 



Vomer 



Figure 18. — Dorsal view of cranium of Chaunax 

 pictus, UW 20770, 90 mm SL. 



Posttemporal 



Epiotic 



lateral ethmoid 



Supraoccipital 



Sphenotic 



Pterotic 



are characterized by having a spatulate postmax- 

 illary process. The premaxilla of Lophichthys is 

 also quite similar but bears a narrow, tapering 

 postmaxillary process (Figure 20B). The premax- 

 illae of the remaining antennarioid taxa exam- 

 ined are each somewhat different from these and 

 from each other. In Brachionichthys (Figure 20C), 

 the ascending and articular processes are at right 

 angles to the toothed portion of the bone; the 

 toothed portion is unusually short, about as long 

 as the postmaxillary process and considerably 

 shorter than the ascending process. In Chaunax 

 (Figure 20D), the shape and relative proportions 

 of the ascending, articular, and toothed processes 



of the premaxilla are similar to those of Anten- 

 narius and Tetrabrachium; the postmaxillary 

 process, however, is represented by a large flange 

 of bone, broadly connected to the toothed process. 

 In Dibranchus (Figure 20E), the ascending and 

 articular processes together form an acute angle 

 with the postmaxillary and toothed processes; the 

 articular process is nearly as long as the ascending 

 process; and the postmaxillary process is con- 

 nected by bone to the toothed process of the 

 premaxilla for about half its length. 



Palatine arch (Figures 9, 21-25).— A mesoptery- 

 goid is present in Antennarius, Chaunax, and 



399 



