SYLVICOLIDA. 161 
and notch in both mandibles separates it from such of the Vireonide 
as have nine primaries. To the Tanagridz, through the slender- 
billed forms as Chlorospingus, Nemosia, Chlorochrysa, etc., the 
relationship is very close; so much so that, by many, both families 
are included in one. What the real differences are, I may hereafter 
be able to point out more satisfactorily than I can at present. 
The American Motacillidx are distinguished by the emargination 
of the outer, and the great elongation of the inner secondaries, as well 
as by other features referred to under that family. Anthus, in par- 
ticular, differs in the lengthened and slightly curved hind claw. 
There is, perhaps, no family to which the relationship is closer 
than to the Cerebide. Of equally small size, and, to some extent, of 
a somewhat similar style of coloration, it is not to be wondered at 
that many species in each family have been indifferently assigned to 
either. The genus Helminthophaga, for instance, can scarcely be 
so defined as to distinguish it from Conirosirum, excepting by the 
characters of the tongue, so rarely preserved in a skin. What the 
external features of distinction are, I hope to show hereafter. I am 
by no means sure that some species even now retained among the 
Sylvicolidz would not be more appropriately placed in Cerebide, 
as Helminthophaga bachmani, Parula gutturalis, ete. 
The tongue in the Sylvicolidx is horny for the greater portion of 
its extent; more or less deeply bifid at the tip for about one-fourth 
or one-fifth the length, the branches fringed or lacerated along their 
external margin. It is short and rather broad at the base, and not as 
extensible, as in the Cerebidx. The essential difference in structure 
from that of the Cxrebidex seems to be that, in some of the latter, 
as Glossiptila and Certhiola, there is a second vertical plane erected 
along the inner edge of the bifurcation or division of the tip of the 
tongue, and more or less perpendicular to it, which is itself lacerated 
or fringed, so as to increase materially the size of the terminal brush. 
In Chlorophanes and Dacnis this vertical plane is folded outward 
upon the horizontal lamina, and perhaps partially or entirely ad- 
herent, and thickening considerably the inner portion of the fork. 
The primary bifurcation of the tongue, however, in all the Cxrebide, 
is also much deeper (about one-third the whole length), and the 
lateral fringe extends much further along the base. There are other 
differences in the tongues of the Cerebidex, of generic import, which 
will hereafter be dwelt on more at length. 
To the general character of the tongue in the Sylvicolidx, however, 
that of ‘Dendroica tigrina” forms a striking exception in its approxi- 
mation ta the Cerebine character, especially that of Certhiola. The 
11 November, 1864, 
