VIREONID^. 321 



The three strictly deutirostral families of seine birds which still 

 remain for consideration — the Vireonidse, Ampelidae, and Laniadse — 

 differ from those just described in certain common characters. The 

 bill is usually stouter and more hooked, in some forms excessively 

 so, with a deep notch and sometimes a prominent tooth behind it ; 

 the tip of the lower mandible is also more or less notched. The 

 nostrils are lateral, the bristles of the mouth generally well de- 

 veloped. Except in a few species of Vireo and in Amjyelis, there 

 are ten distinct primaries, the outer from one-fourth to one-half the 

 second. The tail is sometimes short and square, sometimes long 

 and graduated. The tarsus is always scutellate^ anteriorly, and 

 exhibits a tendency to subdivision in the lateral plates, very unusual 

 in the families already considered. The basal joints of the toes 

 are also more adherent than in the preceding: sometimes attached 

 throughout, sometimes more free, much as in Troglodytidx. From 

 the typical Turdidse they will be known by the scutellate tarsi, 

 from all of the family by the greater adhesion of toes, and peculiar 

 bill ; from the Troglodytidse by the notch and hook of bill and other 

 characters. The only form resembling Sylmcolidse {Hylophilus) 

 has ten primaries and a more notched bill, as well as more united 

 toes and very large claws. 



While in the characters referred to, the three families differ from 

 those previously under review, their precise limitation among them- 

 selves has been a subject of much difficulty. The proper position 

 of Dulus, especially, has been a matter of considerable doubt, 

 although it seems more properly placed among the Ampelidae, being 

 removed from the Vireonidse on account of its less adherent toes, 

 longer basal phalanges of anterior toes, wider gape, etc. In various 

 respects, too, Ampelis can hardly be combined with Ptilorjonys, as 

 has been done. It may also be a question whether if Am^ielis be 

 united into the same family with Ptilogoinjs and its allies, Collurio 

 may not be appropriately added to it. The Ilyiadestes group of 

 what has usually formed the subfamily of Ptilogonatinse, diflers in 

 the longer tai'si, with undivided plates, more deeply cleft toes, etc., 

 from Plilogonys, and should more properly be approximated to the 

 Turdidse, as will hereafter be explained. 



The following characters will serve to illustrate the peculiarities 

 of the three families : — 



' Except in Myiadestinx, which really belong wilh, or at least near, the 

 Turdidee. 



21 May. 1866. 



