308 Mr. Vicors’s and Dr. HonsrrzLD's Description of the 
In these characteristic peculiarities of the Tenuirostral Birds, 
the Trochilide or Humming-Birds of America display the greatest 
perfection. In them the wing is long, strongly acuminated, and 
formed for a rapid and constant flight. The tail also exhibits 
all the varieties of structure which we are accustomed to observe 
in those birds whose habits are aerial. On the other hand, 
the bill is feeble, and apparently of service only in forming a 
sheath to defend the tongue. The legs also are diminutive, and 
peculiarly weak, apparently of little use but to assist the bird in 
supporting itself when at rest; while the characteristic delicacy 
of those members conspicuously unfolds itself by the downy 
plumage descending from the thighs, with which covering na- 
ture seems to have provided them as a means of warmth and 
defence. | 
The nearest approach to the Humming-Birds is found in the 
Cinnyride of the Old World. A line of distinction, however, is 
drawn between the two families by the comparatively greater 
strength of conformation in both the bill and legs of the latter 
group. The wings also, although still formed for a suspended 
flight, lose the strongly-marked length and acumination of those 
of the Trochilus: they are more rounded, and the first quill- 
feather is short, almost indeed spurious. We do not observe, 
moreover, that varied form of the tail which adds apparently so 
much to the purposes of flight among birds: in some species, 
indeed, the middle tail-feathers are elongated beyond the late- 
ral, but hitherto we have seen no approach to the forked con- 
formation. These two families however, although they may 
thus be distinguished from each other, may yet be united to- 
gether as forming the Normal Group of the Tribe. In comparison 
with the remaining families which form the Aberrant subdi- 
vision of it and lead off to other neighbouring Tribes, they pos- 
sess a generally weaker conformation ; and their mode of taking 
their 
