The Rio Frio comes down from the interior of Costa Rica, and joins the San Juan, near where the latter issues from the lake. The banks of its upper waters are inhabited by a race of Indians who have never been subjugated by the Spaniards, and about whom very little is known. They are called Guatuses, and have been said to have red or light-coloured hair and European features, to account for which various ingenious theories have been advanced; but, unfortunately for these speculations, some children, and even adults, have been captured and brought down the river by the Ulleros, and all these have the usual features and coarse black hair of the Indians. One little child that Dr. Seemann and I saw at San Carlos, in 1870, had a few brownish hairs amongst the great mass of black ones; but this character may be found amongst many of the indigenes, and may result from a very slight admixture of foreign blood. I have seen altogether five children from the Rio Frio, and a boy about sixteen years of age, and they had all the common Indian features and hair; though it struck me that they appeared rather more intelligent than the generality of Indians. Besides these, an adult woman was captured by the rubber-men and brought down to Castillo, and I was told by several who had seen her that she did not differ in any way from the usual Indian type. The Guatuse (pronounced Watusa) is an animal about the size of a hare, very common in Central America, and good eating. It has reddish-brown fur, and the usual explanation of the Nicaraguans is that the Indians of the Rio Frio were called "Guatuses" because they had red hair. It is very common to find the Indian tribes of America called after wild animals, and my own opinion is that the origin of the fable about the red hair was a theory to explain why they were called Guatuses; for the natives of Nicaragua, and of parts much nearer home, are fond of giving fanciful explanations of the names of places and things: thus, I have been assured by an intelligent and educated Nicaraguan, that Guatemala was so-called by the Spaniards because they found the guate (a kind of grass) in that country bad, hence "guate malo," "bad guate,"--whereas every student of Mexican history knows that the name was the Spanish attempt to pronounce the old Aztec one of Quauhtemallan, which meant the Land of the Eagle. I shall have other occasions, in the course of my narrative, to show how careful a traveller in Central America must be not to accept the explanations of the natives of the names of places and things.