14 MUSEUM OF COMPARATIVE ZOOLOGY. [Jan. 



at Para, Senhor Pimenta Bueno directed one of the officers of 

 the Amazonian Steamship Company, Mr. Talisman, to accompany 

 us. Once in the waters of the great river, I divided my forces, 

 in order to survey simultaneously various parts of this vast fresh 

 water system, wishing to ascertain how far the distribution of its 

 inhabitants was local, or whether the same species might be 

 found at the same moment in different parts of the main 

 stream and its tributaries. This precaution led to results 

 which amazed me, though I was in part prepared for it by my 

 knowledge of other aquatic faunae. Not only did I find the 

 number of species in these waters exceeding by thousands 

 all former estimates, but I found their localization so precise 

 and definite, that new combinations occurred at given intervals 

 along the main stream, while every forest lake, and all the lesser 

 water-courses, had their special faunas. I neglected no oppor- 

 tunity of verifying the accuracy of my results, visiting the same 

 regions at different seasons of the year, repeating my collec- 

 tions, that I might have the fullest means of comparison, and, as 

 I have said, stationing my parties at considerable distances, 

 in order that, by making simultaneous collections, we should 

 ascertain what was the range of the species. All my young 

 friends — and those I had with me on the Amazons were chiefly 

 volunteer assistants — gave me most hearty and efficient co-op- 

 eration. Besides rendering much important aid in the general 

 work, and making special collecting excursions on the Rio 

 Tapajos and the Rio Negro, Mr. Dexter prepared a very val- 

 uable collection of birds. In his voyage up the River Tapajos 

 he was accompanied by Messrs. James and Talisman ; on that 

 of the Rio Negro, by Mr. Talisman alone. Mr. James, in 

 company with Mr. Talisman, ascended the River I$a and the 

 River Jutahy, and brought down very valuable additions to our 

 fishes, while Mr. Bourget at the same time was employed in 

 making collections in the River Javary and the Solimoens about 

 Tabatinga. Besides these special excursions, all my assistants, 

 including Mr. Thayer and Mr. Hunnewell, had their separate 

 stations at different times, and made very important local col- 

 lections. Messrs. James and Hunnewell at Obydos, Messrs. 

 Thayer and Bourget at Cudajas, Mr. James at Manacapuru, 

 Mr. Bourget at Santarem. To Mr. Hunnewell, beside his 

 general assistance as a member of the working corps, I am 



