136 Evolution and Distribution of Fishes 



Fig. 15. Chart showing possible outlines of land, by shaded area, as existing 

 in late Old Red or Devonian, and in Carboniferous times. Such is indicated by 

 the distribution of plants, also of freshwater fishes and other animals. 



and extension of the continental masses of the earth are 

 indicated alike over the northern and the southern hemi- 

 spheres. Only thus can one properly explain the continuous 

 range of dipnoan and crossopterygian types in the fossil 

 state; the early and continued residence in America and 

 Australia of types of these or of their descendants; also 

 the lingering existence of the three genera Neoceratodus, 

 Protoptenis, and Lepidosiren in Australia, Africa and 

 South America respectively. If we accept compactness in 

 the land-masses of the globe at this time, it aids in solution 

 of many problems. 



