CIRCLES OF THE SHRIKES AND THRUSHES. 339 
(417.) Thus we see that our new circle has this 
advantage over the old, that the variation of the series 
composing it turns out to be in accordance with the 
variation of all other ornithological groups. It can 
consequently stand three tests, —its circularity, its pa- 
rallelism of analogy with other groups, and its coinci- 
dence with the established mode, or progression, in 
which nature varies her groups. The old group would 
not bear this latter verification, notwithstanding it ap- 
peared to be circular, and notwithstanding its analogies 
could be traced in the family of Merulide, although the 
series in the latter family, being made to correspond with 
the erroneous disposition of that of the Laniade, ne- 
cessarily shared in the error, the analogies being correct, 
but the series in which they are made to follow incorrect ; 
the exposition of the two groups, as now re-formed, 
being as follows :— 
True Circle of True Circle of 
the Shrikes. the Thrushes, 
Lanius. The most typical of their respective families. Meraia. 
Thamnophilus. Bill hooked at the tip. Myothera. 
Edolius. Feet very short. Brachypus. 
Ceblepyrus. Rump feathers more or less rigid. Oriolus. 
Tyrannus. Frequent the vicinity of water. Crateropus. 
(418.) But it is not sufficient that each of the divi- 
sions in these two families, as divisions, are correct ; for 
some of them are either very numerous in species, or 
contain many striking deviations in their form. Be- 
fore, therefore, we can pronounce that either of these 
families are strictly proved, in all their parts, it becomes 
necessary to institute a further analysis, to select any 
one of the subordinate divisions, and to submit its con- 
tents to the very same tests as we have just applied to 
its family, as a whole. For instance, the Mvornerin», 
or ant thrushes, represented by the genus Myothera, is 
one of the divisions, or lesser groups, in the circle of the 
thrushes. Now, is this a truly natural group? that is, 
is it circular? We may fairly conjecture it is natural, 
because its most obvious distinctions are in accordance 
with analogies to be traced in other circles, and with the 
principle of variation. But this, strictly speaking, is 
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