124 Evolution and Distribution of Fishes 



Fig. II. Bothriolepis canadensis, dorsal surface, about three- 

 eighth natural size. (After Patten). 



armored members of the Antiarchi like Bothriolepis (Fig. 

 1 1 ) and Asterolepis, or of the Arthrodira-like Coccosteus 

 and allies, that persist from lower Old Red strata, though 

 altered in the representative species, the rather more agile 

 and still existing Dipneusti are now represented by Phan- 

 eropleuron (Fig. 12.) and Palaedaphus, as compared with 

 Dipterus of the lower rocks. But the crossopterygian group 

 is now a prominent one, and in such genera as Holopty chins, 



