112 MUSCICAPINJE. 



no doubt that the three aberrant families of the 

 Dentirostres unite into a circle of their own, inde- 

 pendent of their connexion to the shrikes (Laniadce) 

 and the thrushes (Merulidce). 



With these preliminary observations on the lead- 

 ing characters of this extensive assemblage of birds, 

 we shall now proceed to the names and definitions 

 of the genera composing it. These appear to be 

 as follows: 1. RHIPIDURA, the Fan-tailed Fly- 

 catchers; 2. MONACHA, the Oriole, or Hooded 

 Fly-catchers; and, 3. MEGALOPHUS, or Great- 

 crested Fly-catchers. These three appear to form 

 the aberrant group, as representing the rasorial, 

 the grallatorial, and the fissirostral types. The 

 fourth genus is TODUS, composed of the well 

 known Todies, or South American Flycatchers. 

 And the fifth is MUSCICAPA, consisting entirely of 

 those, pre-eminently typical, which are restricted 

 to the Old World. 



Our proposition is, that these genera form a cir- 

 cular group. But before we enter into those details 

 by which we hope to substantiate this assertion, let 

 us, in the first instance, briefly state the prominent 

 or typical distinctions of each, and then compare 

 them, in our usual manner, with some other well 

 known and authenticated groups, whose internal 

 relations have stood the test of experience and rigid 

 analysis. And, first, they may be compared with 

 the Orders of Perchers in the following manner : 



