No. I.] NORTH AMERICAN PASSERES. 105 
skull. The vomer is fashioned much as we find it among the 
average oscines, but the maxillo-palatines always depart in their 
pattern from those birds, for they are broad where they come 
away from the maxillaries, and gradually taper to their free 
mesial ends, which are never finished off by a bulbous extremity, 
such as we find in Harporhynchus, for instance, though I have 
found in JZyarchus the points of the maxzllo-palatines bent 
backwards, thus simulating the condition referred to in the more 
highly organized Passeres. We usually find, too, a foraminal 
opening piercing the base of either maxzllo-palatine in the 
Clamatores, a feature especially conspicuous among the larger 
American species, though commonly present in a more or less 
marked degree in them all. 
The interior of the cranial casket seems to offer us no very 
good characters which can be utilized, either in classification, or 
in any way, beyond the question of relative capacity, point to 
the affinities of the several groups under consideration. 
These Tyrant birds always seem to have the sclerotal plates 
of the eyeballs very narrow, and in old specimens these show an 
evident tendency to fuse together, and ina specimen of Sayornis 
nigricans at my hand this has actually taken place. Nothing pe- 
culiar characterizes either the hyoidean apparatus or the ossicles 
of the ears. The mandible is not much stronger, in comparison 
with the size of the various species, than we find it among birds 
of an equal size in the oscine group; and in Lanzus it is much 
the stronger. J/yzarchus ctnerascens, for example, has the sym- 
physis to its mandible wide, shallow, and yet rather deep in the 
antero-posterior diameter; the rami are narrow in the vertical 
direction, the vacuities small, and the articular cups and pro- 
cesses respectively shallow and feebly developed. 
It will be seen from this brief description that very excellent 
differential characters distinguish the skulls of typical oscine 
and clamatorial birds. Not so, however, with the remainder of 
the axial skeleton, nor with the appendicular skeleton ; for in all 
the Zyrannide examined by me I find the vertebral column and 
ribs arranged upon the same plan as in the vast majority of the 
oscines, with shoulder girdle, sternum, and pelvis of the same 
general pattern. One thing must be nevertheless noted, and 
that is, that the skeleton is far more pneumatic among the 
Clamatores than it is usually found to be in the Oscines, — 
