4-t ANNALS NEW YORK ACADEMY OF SCIENCES 



pora Falls are not really falls at all, because during the rainy season they 

 entirely disappear. I fished in their edge during the beginning of the 

 rainy season and found them no barrier to the migration of fishes. 



It is interesting to note that "Pirapora" has been derived by some from 

 pira = fish and pora = port, but I found in Paraguay that the Guaranis 

 spell pora as porta (= beautiful), but pronounce it as pora; hence the 

 word would mean "beautiful fishes" and not "fish port." Either of these 

 names might lead one to think that fishes do not pass these falls, but dur- 

 ing the dry season Pirapora becomes a veritable fish port, because the 

 fishes wait below the falls for the rise of the river at the beginning of the 

 rainy season in order to go farther up the river to spawn. This move- 

 ment upstream is well expressed by the Guaranis by the word piracema 

 (pira = fish, cema = rising) . 



Another interesting waterfall is that of Piracicaba, found in Bio Piraci- 

 caba in the State of Sao Paulo. This fall has been a barrier to most 

 species of fishes, but it has not been the absolute barrier that its name 

 indicates (pira = fish, cicaba = ends). During Piracema the Indians, 

 in their exaggerating way, say that the fishes pile up so deep below the 

 waterfalls distant from civilization that one can walk across the rivers 

 on the backs of the big fishes, and that their wriggling ahout produces a 

 roar like thunder. Even though this is extremely exaggerated, there is a 

 certain element of truth in it. 



In order not to swamp the reader with too much detail, I will directly 

 draw my general conclusion concerning waterfalls, because I have already 

 described the important types of fall and because the remainder of the 

 falls have been described with varying degrees of accuracy by numerous 

 other travelers and explorers. Before drawing these conclusions, it is 

 worth noting that whenever the height of a waterfall is given, it is the 

 maximum distance between the water levels above and below the falls, 

 and not the height of side channels and series of "tumbles" which often 

 furnish ready passages for fishes and other aquatic forms. 



Practically none of the many hundred waterfalls existing in the cen- 

 tral and lower courses of Eio Parana and its affluents. Bios Tiete. Grande, 

 Paranaponema, Ivahy and Tibagy, Eio Uruguay, Eio Tocantins, Eio 

 Xingu, Eio Tapajos, Eio Madeira, Eio Negro and other South American 

 rivers have been barriers to the migration of the fishes, which either 

 spawn in the upper courses of the rivers or live in such environments. 

 The only absolute exception to this conclusion is the Iguassu Falls, which 

 have alread} r been considered. 



The Giral, Theothono, Guaja Mirim and the other 27 Madeira-Ma- 

 more falls, Esperanca of Eio Beni, Alcoboca and numerous other falls 



