132 ON THE CLASSIFICATION OP BIRDS. 
(147.) The true wrens {Troglodytes) have such a 
slight (levelopement of the scatisorial powers, that orni- 
thologists have very generally placed these little birds 
with the goldcrests, or true warblers. The analysis, 
however, subsequently given of this last family, leaves no 
doubt in our mind, that their natural situation is in the 
present group. A very singular part of the economy of 
our common wren has not, we believe, been made known. 
If attentively observed, it will he seen that, on flying 
into a hedge or thicket, it almost invariably enters that 
part nearest the ground, and emerges towards the top ; 
if watched within such retreats, its progress is always 
upwards ; and although it hops, rather than climbs, still 
the elongation of the hind toe is evidently intended to 
assist its progressive ascent, slight, indeed, hut continued. 
Again, it is perfectly clear, that wherever the Ameri- 
can wrens {Thrwthorus Vieil.) are placed in a natural 
arrangement, ours must follow; for a separation so 
forced, would, in our opinion, be sufficient of itself to 
shake the very foundations of any system in which the 
two groups were widely separated. Lastly, it will appear, 
upon analysis, that the true wrens are actually repre- 
sented among the warblers, by a genus (Prinia) hitherto 
stationed among the climbing creepers. In this rapid 
sketch of tile animal kingdom, we are compelled to pass 
over details; but we must occasionally notice such as 
these, not only to give the reader a sufficient insight 
into our own views, but to explain upon what grounds 
we venture to question the correctness of all those emi- 
nent naturalists who have gone before us. 
(148.) The structure of the Picina?, or woodpeck- 
ers, constitute them the most perfect of all the climbing 
birds, for nature has rendered their whole organisation 
subservient to this particular power. The feet, although 
very short, are unusually strong ; the nails are broad 
and crooked, and the toes placed in pairs, — that is, two 
forward and two backward. As an additional and a 
powerful support to these birds in their rapid and per- 
uentlicular ascent up the trunks of trees, their tail- 
