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NATURAL HISTORY. [NEW BUILDING. 
The Passeres of Linnaeus* which contain the greater 
part of these birds, have three toes in front and one behind. 
The two outer toes are generally united together at their 
base. 
The wide-gaped Passerine Birds* or Fissirostres, 
which feed chiefly on the wing* have generally very short 
weak feet* and large gaping mouths; they live principally 
on insects* though a few of the larger kinds catch fish. 
Thefamiiyof Goat-suckers (Caprimulgidce, Cases36 and 
37) are nocturnal birds* and have the soft downy plumage* 
and dingy colours of that tribe. They are generally solitary* 
living on moths, and laying their eggs on the ground with¬ 
out any nest. The Leona Goat-sucker* from Africa* is pecu¬ 
liar for having a very long feather arising from the middle 
of each of its wings. The New Holland and South Ame¬ 
rican Podargi * are much larger than any of the individuals 
belonging to the family of the true Goat-suckers* and lay 
their eggs in hollow trees; and the Steatornis is peculiar 
as yielding oil that is used for domestic purposes in South 
America* and also as furnishing large quantities of manure. 
The family of Swallows (Hirundmidce : * Case 38) have a 
close plumage* short bill* extremely long wings* and fly 
with great rapidity; they are generally birds of passage* 
and often live in flocks* as the Swifts* which have all the toes 
in front. Some have the end of the tail feathers rigid like 
the Woodpeckers ; and the Esculent Swallow forms a 
nest of sea-weed* which is used as food in China/and forms 
no unimportant article in the commerce of that country. 
The family of Todies ( Todidte, Case 39) have a broad 
depressed flattened beak* blunt at the end* with rather 
elongated legs* and a short tail. They live on flies, build¬ 
ing their nest on the ground. 
The family of Curucuis ( Trogoriidce * Case 40) have a 
short conical beak. They are covered with very tine* soft 
feathers ; many of them are beautifully coloured *• they 
live chiefly in low damp woods* in tropical parts of 
America and Asia* flying early in the morning and in the 
evening; they build in holes in trees* living on insects* 
and often sit for hours at a time alone on the low branches 
of trees. Some have the upper tail and wing-coverts much 
elongated, and drooping over the wings and tail. 
The King-fishers ( Alcedinidce , Cases 41 and 42) have 
a long quadrangular bill* long wdngs* and very small 
