376 



DR. R. W. SHUFELDT's MORPHOLOGICAL 



Chcetura. 



1. Superior mandible wide and not 

 produced. 



2. Triangidar 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 mesiallj. 



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. 



TrocJiilus. 



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 anchylosed 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 Micropus, 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 

 and 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 

 TrocJiilus. 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. 



