37G 
DR. R. AV. SUUFELDX’S MORPHOLOGICAL 
Chcetura. 
1. Superior mandible wide aud not 
produced. 
2. Triangular openings between nasals 
and frontals, divided by the pre- 
maxillary. 
3. Cranium above smooth and 
rounded. 
4. Vomer truncated. 
5. Maxillo-palatines prominent and 
produced well backwards, tending 
to approach mesially. 
6. Postero-external angles of palatines 
produced as prominent processes. 
7. Palatine heads of pterygoids nearly 
meet mesially. 
8. Pars plana small and formed as in 
Swallows. 
9. Interorbital septum shows several 
vacuities, and these are distinct from 
those on the posterior orbital wall. 
10. Mandible a wide V, without ramal 
vacuity. 
Trochilus. 
1. Superior mandible narrow and 
usually twice as long as the head. 
2. No such openings present. 
3. Cranium above showing a deep, 
longitudinal groove for ends of 
hyoid. 
4. Vomer long and spine-like. 
5. Maxillo-palatines not prominent, 
rounded, and wide apart. 
6. External margin of each palatine 
nearly straight, and no angle 
present. 
7. Palatine heads of pterygoids widely 
separated mesially (and I have seen 
specimens where they anchylosecl to 
the palatines). 
8. Pars plana very large, and very 
different from the Swallows. 
9. Interorbital septum never shows 
but one vacuity, which merges with 
one that absorbs nearly all the 
posterior orbital wall. 
10. Mandible a long and extremely 
narrow V, with ramal vacuity. 
In short, these skulls evidently belong to very different Orders 
of birds, and their differences upon a lateral view can be well 
appreciated by examining and comparing figures 24 and 27 of 
Plate XXII. ; the Swift there figured, however, is Alicropus, but 
will answer just as well. 
Carefully comparing the brain in several specimens of Hum- 
ming-birds of different species, with the brains of Swifts and 
Swallows, I find that, although in all three groups the brain 
aud its parts are strictly fashioned upon the true avian plan, in 
the Swifts and Swallows its general and special form is far 
more alike than it is when we compare it with the brain in a 
Trocliilus. This we might naturally have looked for, since 
the inner shape of the cranial casket in the Humming-bird is 
very different from the corresponding cavity in the Cypseli and 
Hirundines. 
Another structure which need not detain us long is the tongue. 
