624 Subclass Dipneusti, or Lung-fishes 



(4) The Dipneusti probably originated from more specialized 



Crossopterygii, e.g., from the neighborhood of the 

 Holoptychiida. 



(5) The Teleostei differ in so many respects from the Chon- 



drostei that they should rank as an order, in which 

 the Holostei are included. 



