HOW THE FISHES LEAKNED TO SWIM HEINTZ 243 



Avd. Teleostomi. 



Figure 11. — Gradual evolution of different Teleostomes in the direction of better and bet- 

 ter adaptations to swimming. A, a Crossopterygii {Holoptychius) from the Devonian ; 

 B, a Dipnoi (Dipterus) from the Devonian ; C, a Chondrostei {Amblypterus) from the 

 Permian; D, a Holostei {Lepidotus) from tlie Jurassic; E, a Teleostei, a recent 

 maclserel. (Chiefly after Traquair and Woodward.) 



very good swimmers and have in all probability preferred to live 

 near the bottom. Their inner skeleton is weakly ossified. The same 

 is also true of the Dipnoi (fig. 11, B, C, D, E; fig. 12, B, C, and D). 



111666 — 35 17 



