PERCIFORM FISHES — GOSLINE 



77 



Table 2. — Basal characteristics 



ZOARCEOIDAE 



Tendency toward elon- 

 gation 



Tendency toward pelvic 

 reduction 



NOTOTHENIOIDAE 



Tendency toward flat- 

 tening of the head 



Tendency toward spread 

 of pelvics with reten- 

 tion of 5 soft rays 



Tendency toward disin- 

 tegration of circum- 



orbital chain of bones 

 Parasphenoid and fron- 



tals always form a stay 



excluding the prootic 



from the orbital border 

 Basisphenoid never 



present 

 Medial extrascapular 



always fused with 



cranium 

 Pectoral actinosts usually 



4, broad 



All cold water forms Cold water forms Tropical forms 



One nostril on each side One nostril Two nos- 

 trils 



Tendency toward disin- 

 tegration of circum- 

 orbital chain of bones 



Parasphenoid and fron- 

 tals never form a stay 

 excluding the prootic 

 from the orbital border 



Basisphenoid usually 

 present 



Medial extrascapular 

 rarely fused with 

 cranium 



Pectoral radials 3 or 4, 

 broad 



Trachinoid-Blennioid- 

 Congrogadoid Series 



Various, but the head 

 usually not flattened 



Tendency to use the pel- 

 vies as props under the 

 body with a strength- 

 ening of the outer rays 

 and incision of the 

 membrane between 

 them 



Tendency toward consoli- 

 dation of circumorbital 

 bones 



Parasphenoid and frontals 

 usually exclude the 

 prootic from the orbital 

 border 



Basisphenoid usually 

 present 



Medial extrascapular 

 usually fused with 

 cranium 



Pectoral radials 4, vari- 

 ously shaped 



All tropical forms 



Two nostrils 



