EXTERNAL ANATOJIY. TARSAL SCALES. 117 
brethren. However this may be, the facts cannot he 
disputed; and they place in a very strong light the 
necessity of paying great attention to the scutulation of 
the tarsi in nearly aU ornithological groups, but parti- 
cularly in the order of I’erchers. In further proof of 
the last position, w'e may advert to the family of the 
Ampelidne, or chatterers, the typical groups of which 
{Ampelis and Casmurhynchus) have the lateral and pos- 
terior scales oval, and very small, while the anterior are 
very broad, and embrace one half of the circumference 
of the tarsus: this structure, with some very slight dif- 
ferences, extends to all those groups, as Psaris, Pnchy- 
rhynchus, Querula, &c., which are nearly connected to 
the AmpeUd<e, although not in the family circle. It 
would be nearly impossible, and altogether tedious, were 
we to describe the different patterns which the lateral 
scales assume on the tarsi of the different genera : those 
we have already noticed will be sufficient to direct the 
attention of our readers to the subject. 
(108.) Posterior scales are more rarely seen among 
the perchers than either of the preceding series ; and in 
that order they seldom extend, even when they are 
present, much farther than the upper part of the tarsus 
adjoining the knee : they do not exist in the robin, 
their use being superseded by the junction of the lateral 
scales behind, which thus form a sharp ridge or keel. 
In the Tyranniila calcarata [fig. fil.) these scales are 
perhaps more developed than in any other percher, as 
in this bird they form 
a short line of acute 
but very small spines, 
which would almost 
tempt us to believe 
they were employed as 
a means of defence, 
something analogous to 
the spurs of gallinace- 
ous birds. Through- 
out the Tanager family we find no instance of posterior 
I 3 
