In the forests were various beasts still unfamiliar to zoologists, such as the milta, which I have seen twice, a black doglike cat about the size of a foxhound. There were snakes and insects yet unknown to scientists; and in the forests of the Madidi some mysterious and enormous beast has frequently been disturbed in the swamps-possibly a primeval monster like those reported in other parts of the continent. Certainly tracks have been found belonging to no known animal-huge tracks, far greater than could have been made by any species we know.