490 Evolution and Distribution of Fishes 



such land outlines as are set forth in the diagram that forms 

 Figure 23 (p. 179), and which represents the views of 

 Koken and Arldt for land areas of the Triassic period. The 

 old idea of persistence of continental land masses would in 

 no way furnish an explanation. Though we could wish for 

 more numerous examples of species and genera than those 

 above described, the recording of Lepidotiis mawsoni from 

 Eastern Brazil and from Cretaceous beds there, as well as 

 of fragments of doubtful species from India of approxi- 

 mately the same age, indicate that these lingering remnants 

 of the once abundant Jurassic Semionotidae, took advantage 

 of the same migrational pathways as did more evolved 

 groups already reviewed. 



The soft cartilaginous body of the Chondrosteans, 

 seems to have militated against their frequent preservation. 

 But the known remains emphasize an exactly similar conti- 

 nental relation as do the Semionotidae and some others 

 already dealt with in this chapter. Thus the two genera 

 Catopteriis and Dictyopyge, first known in the latter genus 

 from the Bunter or Lower Triassic beds of Switzerland, 

 probably spread eastward and then southward till they 

 reached N. S. Wales and S. Africa, also westward over a 

 wide area of the Eastern States. The related genera 

 Belonorhynchus and Sanrichthys extend In one or other 

 genus from England and Germany to N. Italy and Austria, 

 also In the species B. gracilis and B. gigas to the upper 

 Trias of N. S. Wales. 



In view then of the facts set forth in the last few pages, 

 we must conclude that one or more extensive land-masses 

 stretched In Triassic and Jurassic times, from the Eastern 

 U. S. to India and S. Siberia. Also that such northern land 

 or lands were so related at some point or points with the 

 African continent, that frequent migration of different 

 groups of freshwater fishes took place till S. Africa was 

 reached. The bridge or passage-way must have been a fairly 

 easy and continuous one, but from all present evidence most 

 of this has been destroyed, or has failed as yet of recogni- 

 tion. Finally either from S. Africa across Gondwanaland, or 

 from S. Europe by Persia and India long-continued connec- 

 tion must have been kept up with Australia In Its N. S. 



