In lakes and rivers dwells the water-dog, called by the Guaranies aguarà, and I have often seen it in plains near the shore. Though larger than a mastiff it is afraid of every thing, takes to flight on espying a man at a distance, and is an object of fear to no one. Its ears resemble those of an ass, its head that of a dog. It has plenty of strong and sharp teeth. By night it roars very loud, and lies in wait for lesser animals. The Abipones hunt it for the sake of its skin alone, which is shaggy, of a dark yellow colour, and marked along the back with a black line like an ass. Its hair is extremely soft and much valued by the Spaniards on account of its efficacy in assuaging sciatica, gout, and pains in the bowels. Some lay it upon saddles, finding its warmth extremely salutary. On returning from Paraguay I brought some of it home, but it was stolen from me, a loss which I regret to this day. THE YGUARÒ, OR WATER-TIGER. This beast, which is larger than a mastiff, is generally concealed under deep water. It is shaggy, with a long tail, ending in a point, and is armed with very strong nails. It lays hold of horses and mules, as they are swimming across rivers, and drags them to the bottom. Shortly after, the bowels of the animal, which it has torn to pieces, are seen floating on the surface of the water. The yguarò generally dwells in deep gulphs of rivers, but digs large caverns in the higher banks, where it can hide both itself and its offspring. On the high shores of the Paraguay, we often heard a tremendous noise in our nightly navigation, and the sailors and soldiers informed me that it proceeded from those caves, which were hollowed by the continual dashing of the water, and had at length begun to gape. THE AÒ.