170 
ON THE CLASSIFICATION OF BIRDS. 
manner in which the primary groups pass into each 
other: such assertions, when not founded upon com- 
plete analysis, can only be received as mere opinions : 
we shall therefore merely offer a few remarks on the 
analogy of the pigeons to the Grallatores, in further 
proof of the station given to this family in our arrange- 
ment of the Rasores. 
( I <12.) On looking to the three aberrant groups of the 
Ramres, in reference 'to the primary orders of birds, 
the ostriches (Slruthionida;) evidently represent the 
NatatoreSy by their broad, depressed, andsomewhat duck- 
shaped bill — by theirimperfecttoes — by their greatsize — 
and, lastly, by the wings being as unserviceable for flight 
as are those of the penguin. Here, then, we have a 
certain point from whence to start ; and the question be- 
comes reduced to the narrower compass of which family, 
in short, represents the Grallatores and the Tenui- 
rostrcs. These groups, it will be remembered, are re- 
markable for their soft and slender bills; so also are the 
pigeons : the nostrils are large, long, and covered by a 
thin soft membrane : the pigeons are the only Gallimcea 
•which answer to this description ; they have the most 
slender hills, and their nostrils are long, large, and soft. 
Grallatorial birds have great strength and power of wing : 
thehumming..birds,— agrallatorial type,— flyswifter than 
swallows : and pigeons are the only rasorial birds which 
possess this power to any extent; for it is 'well known 
their flight, in general, is very rapid. The wading 
order is particularly remarkable for being destitute of 
crests, — one of the most distinguishing characters of 
the Scansores and the Rasores : so also are the pigeons 
one species only out of near 150 being furnished with 
tMs appendage; this being a rasorial type in its own 
circle, finally, we have a singular analogy preserved 
between the cuclcows and the pigeons, by the rump 
feathers being of that peculiar formation which belongs 
to the orioles, the caterpillar-catchers, and several 
other tenuirostral types scattered among the perchers. 
With these strong relations before us, we feel no doubt 
