244 The Naturalist in La Plata. 



size, and in other respects. Some have a spiral 

 passage-way leading from the entrance to the nest 

 cavity, and the cavity is in many cases only large 

 enough to accommodate the bird ; but in the 

 gigantic structure of Homorus gutturalis it is so 

 large that, if the upper half of the nest or dome 

 were removed, a condor could comfortably hatch 

 her eggs and rear her young in it. This nest is 

 spherical. The allied Homorus lophotis builds a 

 nest equally large, but with a small cavity for the 

 eggs inside, and outwardly resembling a gigantic 

 powder-flask, lying horizontally among the lower 

 branches of a spreading tree. Pracellodomus sibila- 

 trix, a bird in size like the English house sparrow, 

 also makes a huge nest, and places it on the twigs 

 afc the terminal end of a horizontal branch from 

 twelve to fifteen feet above the ground ; but when 

 finished, the weight of the structure bears down 

 the branch-end to within one or two feet of the 

 surface. Mr. Barrows, who describes this nest, 

 says : " When other branches of the same tree are 

 similarly loaded, and other trees close at hand bear 

 the same kind of fruit, the result is very picturesque." 

 Synallaxis phryganophila makes a stick nest about 

 a foot in depth, and from the top a tubular passage, 

 formed of slender twigs interlaced, runs down the 

 entire length of the nest, like a rain-pipe on the 

 wall of a house, and then becoming external slopes 

 upward, ending at a distance of two to three feet 

 from the nest. Throughout South America there 

 are several varieties of these fruit-and-stem or 

 watering-pot shaped nests; they are not, however, 

 all built by birds of one genus, while in the genus 



