I was sorry to be obliged to leave this beautiful, though almost uninhabited, country so soon, our journey through it having been a mere tourist's gallop. Its vegetable and animal productions, of which we had obtained merely a glimpse, so to speak, were evidently different from those of the alluvial plains of the Amazons. The time we had spent, however, was too short for making a sufficient collection of specimens and facts to illustrate the amount and nature of the difference between the two faunas: a subject of no small importance as being calculated to throw light on the migrations of species across the equator in South America. In the rocky pools near Juquerapuá we found many species of fresh-water shells, and each of us, Mr. Leavens included, made a large collection of them. One was a turret-shaped univalve, a species of Melania, every specimen of which was worn at the apex; we tried in vain to get a perfect specimen. In the crystal waters the fishes could be seen as plainly as in an aquarium. One kind especially attracted our attention, a species of Diodon, which was not more than three inches long and of a pretty green colour banded with black; the natives call it Mamayacú. It is easily caught, and when in the hand distends itself, becoming as round as a ball. This fish amuses the people very much; when a person gets corpulent, they tell him he is as fat as a Mamayacú.
At night I slept ashore as a change from the confinement of the canoe, having obtained permission from Senhor Joaquim to sling my hammock under his roof. The house, like all others in these out-of-
