﻿MIRANDA RIBEIRO, ON FISHES FROM THE IPORANGA RIVER. 3 



to the shore, in spite of the light of a candle standing about 

 20 centimeters from its body. But, if one touches slightly 

 the water, the fish gets away very nimbly. In a spöt where 

 the water was about 50 centimeters deep, I put a small 

 net for butterflies in order to catch the fishes, and as soon 

 as I put in the net small pieces of the gut of a squirrel 

 I had brought for the purpose, the fishes came from both 

 sides of the river, not only against but even with the stream, 

 evidently following a sensation which did not permit them to 

 loose much of the way for reaching the bait. It seems to 

 me that the oldest creatures like to live apart from the 

 young ones, in deeper water. In an aquarium they eat earth- 

 worms, never insects or vegetable matter, excepting some 

 algae. The water of the cave in summer, is shallow and 

 clear, but somewhat saturated with calcitic salts; during the 

 rainy season the matter must be different, in these tunnels 

 as the clay of the bottom found near the roof indicates. When 

 the water is clayey, the fishermen of Iporanga sometimes catch 

 blindfishes with hooks, in the neighbourhood of the entrance, 

 outside the cave.» 



Amongst the specimen sent to me by Mr. Krone, one 

 is provided with an eye on one side only. Tliis fact states 

 the reversion by inheritance to the character of its ancestors ; 

 the organ is 4 millimeters in diameter and the fish 150 

 mm. long. 



This very striking fact is a valuable document for the 

 genealogical theory of Lamarck and IJarwin, when one may 

 state in 35 other captured, young and adult animals, the 

 complete absence of such an important organ. 



In the dissected animal I was not able to see the opti- 

 cal nerve: through its normal place passed the strong ner- 

 vöns branch of the maxillary barbel. 



The evolution of the organ of sight does not permit dis- 

 cussion here. Another noteworthy fact is that evolution in 

 this fish only, when the lower and open course of the Iporanga 

 system is inhabited by many other species, the greater num- 

 ber of which is also found in the Parana system. As this 

 fact may pro ve the ancient connection of these systems, in 

 other times, it may also prove that all the fluviatic species, 

 now found in the lower course of the Iporanga, had passed 

 through the vicinity of the divortium aqiiarum of these systems . 



