38o NOTES OF A BOTANIST 
are (with one notable exception ^) no aquatics and 
no shore grasses. Compare this with the broad 
fringe of tall, succulent, amphibious grasses on the 
shores of the Amazon, or detached and floating down 
it in the shape of large islands, and of luxuriant 
aquatics, some fixed by roots, others floating 
(Victoria, Jussiaea, Pontederia, Frogbits, Azolla, 
Salvinia, Pistia, etc.), in deep still bays, but especi- 
ally in lakes and channels communicating with the 
main river. 
Some of the tributaries of the Rio Negro, how- 
ever, have plenty of fish, namely, those of more or 
less turbid water, of which the Rio Branco holds 
the first rank, and after it come the Marania and 
Cauaboris, all entering on the left bank. In these 
rivers many Amazon fish are said to be repeated. 
About the mouth of the Rio Branco is the only 
place in the Rio Negro where the Pirarucii is found 
— that noble and remarkable fish, so characteristic 
of the Amazon. With the exception of the Pirarucii, 
most of the larger fish of the Amazon recur on the 
Upper Orinoco, above the cataracts ; at least the 
Indians assert them to be the same, and to unskilled 
eyes they are undistinguishable. The Valenton 
or Lablab of the Orinoco, for instance, is surely 
the same as the large Pirahyba of the Amazon ; 
the Pavon as the Tucunare ; the Rallado as the 
Surubi'm ; the Muruciitu as the Tambaqui ; the 
Cajaru as the Pira-arara, and so on. 
Many of the fishes of the Rio Negro travel up it 
to spawn, and especially up some of its tributaries ; 
but the wanderings to and fro of fish in quest of 
^ That of the Podostemons on granite rocks in the falls and rapids. 
