350 Evolution and Distribution of Fishes 



reserve we would suggest, lived in Central America or 

 Northern S. America. The only fossil genus is Tetra- 

 gonopterus, of which two species have been described from 

 the "Tertiary Lignite" of Sao Paulo, Brazil, while about 

 50 living representatives of it occur over Northern S. 

 America, and one is found as far north as the Rio Grande 

 of Western Texas. By utilization of the Cretaceous-Eocene 

 brfdge — that later is emphasized — the group evidently 

 reached and spread widely across the freshwaters of Africa 

 (p. 421) where the family is now richly represented. 



The Cyprinidae started probably from common ancestry 

 with the last, and from, or near, the same centre, but be- 

 came distributed north-eastward and northward through 

 freshwaters of N. America, of Europe and of Asia, while 

 a few entered N. Africa (Fig. 70, p. 417). The oldest 

 fossil types are from the Lower Tertiary beds of America. 

 In more recent Miocene beds of Europe, and in (Upper?) 

 Miocene strata of Sumatra several genera have been recog- 

 nized. 



The third family Siluridae with the highly modified 

 derivative families Loricaridae and Aspredinidae, starting 

 probably from like ancestry as the two last seem then to 

 have evolved in the central and southern parts of the U. S., 

 where Rhineastes was abundantly represented in early Eo- 

 cene times, then they seem to have spread mainly along 

 the northern side of Gondwana continent, made northward 

 connections by means of Ariiis and Bticklandium into the 

 Atlantis continent when it was continuous with Europe, 

 while in late Miocene or early Pliocene days the family 

 reached tropical Asia. The last derivatives we would re- 

 gard — as do ichthyologists generally — as the most highly 

 modified of the three series (Fig. 69, p. 416). 



If now we review the above three families somewhat 

 more in detail, it may be said that the Characinidae is a 

 purely freshwater group that includes many genera and 

 about 600 species, that are constantly being added to by 

 Boulenger, Eigenmann, and others, as African and S. 

 American lakes and rivers are explored. Though known 

 only by Tetragonopterits in the fossil state, we confidently 

 predict that other and even Cretaceous genera will yet be 



