146 THE TOCANTmS. Chap. IV. 



Mr. Leavens brought the reptile down with a charge 

 of shot. 



Septertiber 26fh. — At length w^e got clear of the 

 islands, and saw once more before us the sea-like 

 expanse of waters which forms the mouth of the 

 Tocantins. The river had now sunk to its lowest point, 

 and numbers of fresh-water dolphins were rolling about 

 in shoaly places. There are here two species, one of 

 which was new to science when I sent specimens to 

 England ; it is called the Tucuxi (Steno tucuxi of 

 Gray). When it comes to the surface to breathe, it 

 rises horizontally, showing first its back fin ; draws an 

 inspiration, and then dives gently down, head foremost. 

 This mode of proceeding distinguishes the Tucuxi at 

 once from the other species, which is called Bouto or 

 porpoise by the natives (Inia Geoffroyi of Desmarest). 

 When this rises the top of the head is the part first seen ; 

 it then blows, and immediately afterwards dips head 

 downwards, its back curving over, exposing succes- 

 sively the whole dorsal ridge with its fin. It seems 

 thus to pitch heels over head, but does not show 

 the tail fin. Besides this peculiar motion, it is 

 distinguished from the Tucuxi by its habit of gene- 

 rally going in ]Dairs. Both species are exceedingly 

 numerous throughout the Amazons and its larger 

 tributaries, but they are nowhere more plentiful than 

 in the shoaly water at the mouth of the Tocantins, 

 especially in the dry season. In the Upper Amazons a 

 third pale flesh-coloured species is also abundant (the 

 Delphinus pallidus of Gervais). With the exception 

 of a species found in the Ganges, all other varieties 



