22 RIO DE JANEIRO chap. 



tricate wilderness of lakes ; in some of which were fresh, in 

 others salt water shells. Of the former kind, I found a Limnsea 

 in great numbers in a lake, into which the inhabitants assured 

 me that the sea enters once a year, and sometimes oftener, and 

 makes the water quite salt. I have no doubt many interesting 

 facts in relation to marine and fresh-water animals might be 

 observed in this chain of lagoons which skirt the coast of Brazil. 

 M. Gay ^ has stated that he found in the neighbourhood of Rio 

 shells of the marine genera solen and mytilus, and fresh-water 

 ampullariae, living together in brackish water. I also fre- 

 quently observed in the lagoon near the Botanic Garden, where 

 the water is only a little less salt than in the sea, a species 

 of hydrophilus, very similar to a water-beetle common in the 

 ditches of England : in the same lake the only shell belonged 

 to a genus generally found in estuaries. 



Leaving the coast for a time, we again entered the forest. 

 The trees were very lofty, and remarkable, compared with those 

 of Europe, from the whiteness of their trunks. I see by my 

 notebook, "wonderful and beautiful flowering parasites," invari- 

 ably struck me as the most novel object in these grand scenes. 

 Travelling onwards we passed through tracts of pasturage, much 

 injured by the enormous conical ants' nests, which were nearly 

 twelve feet high. They gave to the plain exactly the appear- 

 ance of the mud volcanoes at Jorullo, as figured by Humboldt. 

 We arrived at Engenhodo after it was dark, having been ten 

 hours on horseback. I never ceased, during the whole journey, 

 to be surprised at the amount of labour which the horses were 

 capable of enduring ; they appeared also to recover from any in- 

 jury much sooner than those of our English breed. The Vam- 

 pire bat is often the cause of much trouble, by biting the horses 

 on their withers. The injury is generally not so much owing to 

 the loss of blood, as to the inflammation which the pressure of the 

 saddle afterwards produces. The whole circumstance has lately 

 been doubted in England ; I was therefore fortunate in being 

 present when one (Desmodus d'orbignyi, Wat.) was actually 

 caught on a horse's back. We w^ere bivouacking late one 

 evening near Coquimbo, in Chile, when my servant, noticing 

 that one of the horses was very restive, went to see what was 

 the matter, and fancying he could distinguish something 



1 Annales des Sciences Natiirelles for 1833. 



