The HoLARCTIC Region, comprising North America and the extratropical mass of land of the Old World, may from an ornithological point of view be characterized by the Colymbi, Alcidae, Gallidae or Alectoropodous Galli, and the Oscines, which have here reached their highest development; while Ratitae, Tinami, Psittaci, and non-Oscine Passeres (with the exception of Tyrannidae extending into North America and Conurus carolinensis) are absent.
The close affinity of North America with the Palaearctic avifauna becomes at once apparent if we exclude those groups of birds which we have good reason to believe have their original home in the Neotropical region, notably numerous Tyrannidae, humming-birds and the turkey-buzzards.
For 5 Not literally, because a few other forms such as the genera Polioptila and Ptilogonys, now known to have no relation to the Tyrannidae, were included, though these forms, it would seem, had never been dissected by him.
But again Muller made his third " tribe " Picarii also to contain the Tyrannidae, of which mention has just been made, though it is so obvious as now to be generally admitted that they have no very intimate relationship to the other families with which they are there associated.