112 RIVER PORPOISES. 



The heat augments sensibly in the Llanos during the 

 rainy season, particularly in the month of July, when the 

 sky is cloudy, and reflects the radiant heat toward the earth. 

 During this season the breeze entirely ceases ; and, accord- 

 ing to good thermometrical observations made by M. Pozo, 

 the thermometer rises in the shade to 39 and 39 '5, though 

 kept at the distance of more than fifteen feet from the 

 ground. As we approached the banks of the Portuguesa, 

 the Apure, and the Apurito, the air became cooler from the 

 evaporation of so considerable a mass of water. This effect 

 is more especially perceptible at sunset. During the day 

 the shores of the rivers, covered with white sand, reflect 

 the heat in an insupportable degree, even more than the 

 yellowish brown clayey grounds of Calabozo and Tisnao. 



On the 28th of March I was on the shore at sunrise to 

 measure the breadth of the Apure, which is two hundred 

 and six toises. The thunder rolled in all directions around. 

 It was the first storm and the first rain of the season. The 

 river was swelled by the easterly wind ; but it soon became 

 calm, and then some great cetacea, much resembling the 

 porpoises of our seas, began to play in long files on the 

 surface of the water. The slow and indolent crocodiles 

 seem to dread the neighbourhood of these animals, so noisy 

 and impetuous in their evolutions, for we saw them dive 

 whenever they approached. It is a very extraordinary phe- 

 nomenon to find cetacea at such a distance from the coast. 

 The Spaniards of the Missions designate them, as they do 

 the porpoises of the ocean, by the name of toninas. The 

 Tamanacs call them orinucna. They are three or four feet 

 ,ong; and bending their back, and pressing with their tail 

 on the inferior strata of the water, they expose to view a 

 part of the back and of the dorsal fin. I did not succeed 

 in obtaining any, though I often engaged Indians to 

 shoot at them with their arrows. Father Gili asserts 

 that the Gumanos eat their flesh. Are these cetacea 

 peculiar to the great rivers of South America, like the 

 manati, which, according to Cuvier, is also a fresh water 

 cetaceous animal ? or must we admit that they go up from 

 the sea against the current, as the beluga sometimes does in 

 the rivers of Asia ? What would lead me to doubt this last 

 supposition is, that we saw toninas above the great cataracts 



