CATALOGUE 



BIRDS. 



Order IV. PSITTACI. 



Feet permanently zygodactyle by reversion of the fourth toe, 

 covered with rugose granular scales or plates ; bill short, extremely 

 stout, strongly hooked or epignathous, and furnished with a cere 

 (frequently feathered) as iu the Birds of Prey. These are the two 

 most obvious characters which distinguish the Parrots. 



Other important characters are the following :— Upper mandible 

 movable, being articulated instead of suturally joined with the fore- 

 head ; its lower surface often with transverse or oblique ridges, 

 producing a file-like surface on the distal palatine portion. Tongue 

 thick and fleshy, in some families peculiarly brushy or fringed. 

 Orbital ring frequently complete by union of the lacrymal bones with 

 postfrontal or postorbital process. Nasal septum extensively ossified. 

 Palate desmognathous. Dorsal vertebra opisthoccelous. Symphysis 

 of lower jaw short and obtuse. Sternum generally fenestrated 

 posteriorly. Furculum weak, sometimes defective or wanting 

 Lower larynx with three pairs of muscles. 



Feathers with aftershafts. Spinal feather-tract on the neck well 

 defined by lateral bare tracts and forked on the upper back. Tail- 

 feathers twelve, only in Oreopsittacus fourteen. 



Oil-gland tufted, or wanting. 



No ca j ca, and gall-bladder generally wanting. 



Carotids, right and left both present and running deep in the 

 vortebrarteri;il canal, or the right one deep and the left superficial, 

 or only the left present (in Cacatna), as usual in birds. 



