INTRODUCTION. l07 



cylindrical, others conical, with an opening at both 

 ends ; and small sharpened sticks are placed, fun- 

 nel-shaped, in such a manner that they point 

 inwards, to allow the fish to get in but not out 

 again. 



We observed, in the Rio Negro, numerous con- 

 trivances at the mouth of small rivers, to secure fish 

 on a similar plan, but on a larger scale. The mouth 

 of the stream is barricaded with high poles, in the 

 following form : 



