308 Mr. ViGORs's a7id Dr. Horsfield's Description of the 



In these characteristic peculiarities of the Tenuirostral Birds, 

 the Trochilidœ or Hummiiig-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 Hummiiig-Birds is found in the 

 CinnyridcE 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 remainino- families which form the Aberrant subdi- 

 vision of it and lead ofi" to other neighbouring Tribes, they pos- 

 sess a generally weaker conformation ; and their mode of taking 



their 



