494 



SYSTEMA TIC SYNOPSIS. — PSITTA CI. 



III. Order PSITTACI: Parrots. 



Feet permanently zygodactyle 

 by reversion of the fourth toe, 

 covered with rugose granular 

 scales or plates; biU short, ex- 

 tremely stout, strongly epigna- 

 thous, and furnished with a (fre- 

 quently feathered) cere, as in the 

 birds of prey ; wings and tail 

 variable. The parrots, including 

 \ P*^ "T^ A^ i ' ^i 'n^BsaBE^ ^^ffiV *^^ macaws, cockatoos, lories, 



X^ tJ^^ ^SHw^ ^^i^ etc., form one of the most strong- 



ly marked groups of birds, as 

 easily recognizable by their pecu- 

 liar external appearance as de- 

 fined by technical points of struc- 

 ture. They were formerly in- 

 cluded in an "order" Scansores 

 on account of the paired toes, but 

 this is a comparatively trivial cir- 

 PIG. 346.- Carolina Parroquet, reduced. (From Tenney, after WUson.) ^^,^^^^^^^^ . they have no special 



affinity with other zygodactyle birds, and their peculiarities entitle them to rank with groups 

 called orders in the present volume. They might not inaptly be styled frugivorotis Baptores; 

 and in some respects they exhibit a vague analogy to the quadrumana (monkeys) among 

 mammals. The tongue is thick and fleshy, in some genera peculiarly brushy ; it is used to 

 some extent in 2)rehension, objects being handled between the tongue and upper mandible. 

 The upper mandible is much more freely movable than is usual in birds, being articulated in- 

 ^iead of suturally joined with the forehead ; and the bill is commonly used in climbing. The 

 bony orbits of the eyes are frequently completed by union of the lachrymal bones with postor- 

 bital ])rocesses, and in some genera develop a bony bridge across the temporal fossa. The 

 symphysis of the lower jaw is short and obtuse. The sternum is entire or simply fenestrated 

 posteriorly; the furculum is Aveak, sometimes defective, or w^anting. The principal metatarsal 

 bone is short and broad, and its lower extremity is modified to suit the position of the fourth 

 toe. The lower larynx is peculiarly constructed, with three pairs of muscles ; the ability to 

 articulate human speech is one of the most notorious faculties of some parrots. The plumage 

 shows aftershafts ; the oil-gland is wanting in certain genera ; when present, it is tufted. 

 There are no coeca, and the gall-bladder is wanting. Though the family is so perfectly 

 circumscribed that no one doubts of any bird whether it be psittacine or not, parrots difi"er re- 

 markably among themselves in certain structural characters which have in most birds a high 

 classificatory value. Thus, there are three decided modifications of the carotid arteries — of 

 which right and left may both be present, and both running deep in the vertebrarterial canal ; 

 or both may be present, but the left superficial ; or only the left, is developed (in Cacatua), as 

 usual in birds. The ambiens muscle, again, may be present and normal, present and incom- 

 plete, or wanting altogether. The femoro-caudal muscle, semitendinosus, and accessory semi- 

 tendinosus are present ; the accessory femoro-caudal is absent. 



The division of the Psittaci into family groups has taxed the ingenuity of ornithologists ; 

 fur so variously interrelated are the numerous forms, that the grouping fluctuates with almost 

 every character or set of characters selected ff)r use in classification. But Garrod's admirable 

 anatomical investigations show that the Psittaci may be ranged in two series, according to the 



