328 Annals of the Carnegie Museum. 



It is generally accepted that Cuba once had surface streams which 

 later became subterranean. The Twin Caves at Mitchell, Indiana, 

 are formed by a cave-in of a part of the roof which formerly covered 

 a continuous underground stream. A similar cave-in has taken place 

 in the case of the Caverna dos Areas, near Iporanga, Brazil, which 

 in addition has its exit stopped up by large rocks and other debris. 

 In fact all of the caves in which blind fishes have been found show 

 abundance of evidence that radical transformations have taken place 

 in their channels during bygone days; while caves like those of Santo 

 Abreu Bahia, of Sao Luiz de Caceres and Coimbra, Matto Grosso, 

 San Matias, Bolivia, Cavernas do Lagoa Santa, etc., of Minas Geraes, 

 Gruta de Alambary, Gruto do Monjolinho, Grata da Arataca, etc., 

 of Iporanga, Brazil, and the numerous caves of eastern Greene County, 

 Indiana, appear to have sufficient food and other favorable conditions 

 for blind fishes, but none of these caves exhibit any signs of radical 

 changes in their channels. Hence it appears that all caves which 

 have had unobstructed channels and mouths with ready exits and 

 entrances have no blind fishes. 



In view of these facts it appears that the "accident theory" is the 

 most probable explanation of the origin of blind fishes in the caves. 



I think that the Iporanga cave region would be the most fruitful 

 place in the world for experimental and cave exploration work, be- 

 cause of the favorable climatic conditions, the extensive caves almost 

 unknown, and the present state of its existing life. 



