BIOLOGY. 815 



entering fresh water belonged to no marine genus ever found in 

 the sea, and the next six or seven which he obtained exhibited 

 the same dissimilai-ity. This was a fact against the theory of 

 migration. It was a general fact, that, within a certain circum- 

 sciibed area eacli fi-esh water tract has its distinct species ; and it 

 was x'emarkable how certain families, or even genera, prevail over 

 others. In comparing the fishes of the northern and southern 

 rivers of Brazil, the difference was found to be still greater, each 

 basin having its sjiecial distribution. 



He drew one general inference from these general statements, 

 namely, that all these fishes are in their natural home, and have 

 not migrated, but have originated where they are found. 



Brazilian Reptiles. — Though sei'pents of great size, power, and 

 virulence, abounded in Brazil, he said he had met with but few ; 

 and there was not much danger to travellers, who could penetrate 

 the woods, or recline among the vegetation with impunity. If 

 serpents were met, it was only as an accident to which men are 

 liable everywhere. 



Though there are many frogs and toads, there are no salaman- 

 ders in Brazil. The tree-toad rivalled in beauty the brilliant 

 plumage of some of the native birds. Then there were barking 

 and crying frogs, whose voices might be mistaken for sounds 

 uttered by large animals or by human beings. There were many 

 varieties of reptiles ; and the same localization prevailed as among 

 fishes. This also prevailed among insects. 



There were in the rivers, he said, a great abundance of turtles, 

 eongreo'atino; in some localities in masses of hundreds of thou- 

 sands, all endeavoring to get on shore to lay their eggs, of which 

 each turtle deposits from eighty to one hundred. There were 

 also terrestrial tortoises. The alligators differed from the croco- 

 diles of the old world in the arrangement of their teeth, and in 

 other respects ,' and the lizards, which were numerous, were chiefly 

 tree-lizards. 



Birds and Mammals. — Of the varieties of the aquatic class of 

 birds found in northern regions, he remarked, there ai'e but few 

 representatives in the Amazonian region. Thei'e are of the 

 swimming birds, some ducks, and a variety of small geese, sev- 

 eral S2)ecies of the latter being unknown at the north. Of the 

 wading birds, there are none resembling our plovers or sand- 

 peejJS ; but the red ibis abounds in such numbers as to obscure the 

 air, and the white hei'ons and the large stoi-ks crowd the surfaces 

 of the pools in the forest, or congregate along their margins. The 

 birds allied to our gallinaceous fowls present a striking feature. 

 One of these, called the unicorn, is as as large as a turkey, and 

 has a horn-like appendage upon its head. There the gallinaceous 

 birds proper do not resemble those of our own country, or of the 

 countries of the East, their characteristic being a heavy build. 



One of the glories of South Amei-ica, he said, was the family of 

 humming-birds. They are found not only in low lands, but in all 

 the valleys of the Andes, in hundreds of varieties. 



He observed that, as with other animals, whatever variety of 

 birds was noted, it was seen that they were specially circum- 



