STUDIES or THE MACROCHIRES. 



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, w^hile in others it 

 possesses marked affinities with the Clamatorial plan of skeletal 

 structure. 



21. Of tie Skull (PL XVII. figs. 4 & G).— We find the superior 

 osseous mandible of Ampelis to be somewhat flattened or com- 

 pressed from above downwards ; tlie 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 IlesperocicJila (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 Tyrannus verticalis (PI. XVII. fig. 3). So 



* Shufeldt, R. W., "Osteology of Ercmophila a/pcstris [Ofocoris alj^csiris 

 arenicold]" Twelfth Annual Report U.S. Geol. and Geog. Surv. of the Territories, 

 1882, p.G52, pi. iv. fig. 22. 



