STUDIES OF THE HACROCHIRES. 
309 
20. The alimentary canal agrees in general with the Passerine 
birds, and a small pair of cceca coli are present. 
The Skeleton o/‘ Ampelis. 
To any one who has examined series of skeletons of Passerine 
birds, it is a well-known fact that, as we pass from one specific 
form to another, from the higher to the lower types of orga- 
nization, or vice versa, we are impressed with the very few and 
inconspicuous structural modifications that we encounter; as we 
serially investigate the allied species of a group or groups, the 
shading of nearly all of the morphological characters of one 
species into those of another, and of the latter into the next 
nearest related form, is, as a rule, extremely gradual, and almost 
beyond the power of the pen to adequately describe. Yet, if we 
choose birds from the extremes of the Passerine order, very 
excellent taxonomic characters are met with, and if closely 
studied often point to affinities otherwise obscure or very 
puzzling. 
As shown in many of the characters of its skeleton, Ampelis 
cedrorum seems to hold a sort of middle position here; and I 
think we shall find that, in some particulars, it is not to be distin- 
guished from the highest types of the Oscines, while in others it 
possesses marked affinities with the Clamatorial plan of skeletal 
structure. 
21. Of the Skull (PI. XVII. figs. 4 & 6). — We find the superior 
osseous mandible of Ampelis to be somewdiat flattened or com- 
pressed from above downwards ; the narial apertures are large 
and subelliptical in outline. This part of the skull is broad 
at its base, tapering rather gradually to its apex ; while above, its 
naso-frontal regions gradually merge into each other, there being 
no well-defined transverse line dividing them. The median 
rhinal partition, or nasal septum, is wholly in cartilage in this 
bird (PI. XVII. fig. 4) — a character wherein it agrees with such 
forms as Hesperocichla (PI. XVII. fig. 5), Merula, and probably 
all the higher Thrushes, as well as with such a type as Otocoris *. 
On the other hand, a very well-developed nasal septum is to be 
found in the skulls of the American Tyrannidce , as, for example, 
in such a Flycatcher as Tyrannies verticalis (PI. XVII. fig. 3). So 
* Skufeldt, K. W., “Osteology of Eremophila alpestris [ Otocoris alpestris 
cirenicola ],” Twelfth Annual Report TJ.S. Geol. and Gfeog. Surv. of the Territories, 
1882, p. 652, pi. iv. fig. 22. t 
