494 



SYSTEMATIC SYNOPSIS. — PSITTA CI. 



III. Order PSITTACI: Parrots. 



Fig. 346. — Carolina Parroqiict, rediiced. (From TcDney, after "S^'"UsOIl.) 



Feet permancntiy zygodoctyle 

 by reversion of the fourth toe, 

 covered with rugose granular 

 scales or plates; Mil short, ex- 

 tremely stout, strongly epig>ia- 

 thous, and furnished with a (fre- 

 quently feathered) cere, as in the 

 birds of prey ; wings and tail 

 variable. The parrots, including 

 the macaws, cockatoos, lories, 

 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- 

 eluded in an ''order" Scansores 

 on account of the paired toes, but 

 this is a comparatively trivial cir- 

 cumstance ; 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 fnigivorous Maptores; 

 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 jjreheusion, 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- 

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

 bony orbits of the eyes are fi-equently completed by union of the lachrymal bones with postiir- 

 bital processes, 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 weak, sometimes defective, or wanting. The principal metatarsal 

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

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

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

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

 There are no eoeca, and the gall-bladder is wanting. Thc_)Ugh the family is so perfectly 

 circumscribed that no one doubts of any bh'd whether it be psittacine m- ntit, parrots difi'er re- 

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

 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 inc(nn- 

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

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



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

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

 every (diaractcr or set of characters selected for use in classification. But Garrod's admirable 

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



