No. 1.] NORTH AMERICAN PASSERES. 83 
It is our aim in the present connection to place before the 
reader a brief, concise sketch of the osteology of one or more 
species of as many of these passerine families as possible, and 
as such work proceeds, compare the salient features of the 
skeleton of any family with the corresponding ones as found in 
species of another or other family or families supposed to be 
more or less nearly affined. Possibly by such means we may be 
enabled to point out, so far as skeletal characters are concerned, 
the relations that some of the groups of this always puzzling 
order to the taxonomist apparently bear to each other, though 
no one is better aware than the writer that such complex ques- 
tions can never be fully determined until the morphology of 
each and a// the species of the Passeres is worked carefully out 
in its minutest details, and this we have spoken of again and 
again in our published memoirs. It is earnestly hoped that the 
work here undertaken may assist matters to that end, and will 
to some degree supplement the able endeavors of former authors 
in the same field.? 
Few ornithologists better appreciate the difficulties which 
still stand in the way of a correct classification of the order 
Passeres than my friend Professor Newton, and this distin- 
guished authority has said that, in referring to this group, 
‘‘ Some two or three natural, because well-differentiated, families 
are to be found in it, — such, for instance, as the Azrundinide, 
or Swallows, which have no near relations; the A/audide, or 
Larks, that can be unfailingly distinguished at a glance by 
their scutellated planta, as has been before mentioned; or the 
Meliphagide, with their curiously constructed tongue. But the 
great mass, comprehending incomparably the greatest number 
of genera and species of birds, defies any surer means of sepa- 
ration. Here and there, of course, a good many individual 
genera may be picked out capable of most accurate definition ; 
but genera like these are in the minority, and most of the re- 
mainder present several apparent alliances, from which we are 
at a loss to choose that which is nearest. Four of the six 
groups of Mr. Sclater’s ‘Laminiplanter’ Osczmzes seem to pass 
almost imperceptibly into one another. We may take examples 
in which what we may call the Thrush form, the Tree-creeper 
1 McGILLIvRay, W., British Birds, I., pp. 485, 486; and PARKER, W. K., Zrans. 
Zo6l. Soc., V., p. 150. 
