472 CERTHIIDÆ.
and some of them placed in very different families. The
affinity between the species of Certhia as now restricted and
some of the true Wrens is very evident, and 011 the other
hand, through several exotic genera, a transition may be
easily traced to the next family to be mentioned, the Sittidce.
Those ornithologists who unite Certhia, Sitta and the intermediate
genera in one family may he justified, but the
systematists who place the Treecreepers near the Woodpeckers
take a very erroneous view of the characters which
really determine the affinities of birds. The Picidce possess
110 structural character in common with the Certhiidce as a
whole which is not shared by many other families that 110 one
has ever thought of allying to the former, for the stiffened
tail-feathers are only found in some forms of the latter and
not generally. There is 110 doubt, it is true, of the two groups
having certain somewhat similar habits, but these do not go
far in classification.
NUTHATCH.
P ASSURES.
SlTTA CÆSIA, Wolf*.
THE NUTHATCH.
Sitta Europoeai.
S it ta , Linnæus %.—l>ill moderate, strong and compressed, the culmen very
slightly arched, the gonys ascending towards the point. Tongue short and horny,
the tip abrupt and furnished with strong bristles. Nostrils basal, rounded,
placed in a deep hollow, covered by hairs and short feathers. Legs short and
stout; the tarsi scutellated ; toes long and strong, the hind toe especially, the outer
toe joined a t its base to the middle toe; claws large and much hooked. Wings
rather long ; the first feather much shorter than the second, the fouith or fifth
the longest. Tail short, flexible, broad and nearly even.
Ou r well-known Nuthatch was long considered the sole
example of its genus in Europe, but not only have other
well-marked species been discovered within the limits of this
quarter of the globe, but our bird has been shewn to differ
from that which wras described by Linnæus sufficiently to
* Taschenb. deutsch. Vogelk. i. p. 128 (1810).
+ Not Sitta europoea, Linnæus. Î Sjist. Nat. Ed. 12, i. p. 177.
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