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 
at 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 
