THE PSITTACINjE. 101 



P. criihacus such a densely feathered stem is visible at the end of the fork. To this may be 

 added, that P. erithacus alone possesses an oil-gland, while the above-mentioned American 

 species certainly have not this organ, but are furnished with scattered powder-down feathers in 

 the posterior portion of the dorsal tract, these being especially distinct in P. ochrocephalus and 

 dufresniantts. 1 The number of remiges in these is twenty-three, and the second, third, and 

 fourth are the longest ; P. crithacus has twenty-four. The inner small humeral tract is certainly 

 present, at least in the American species, but much smaller than in P.pertinax. 



5. Pionus WAGL. Of P. menstruus and purpureus, the only species of this group that I 

 have examined, I can only mention that the oil-gland was entirely deficient, without any powder- 

 down feathers being present. In the wing I found twenty-two obtuse remiges, of which the 

 third is the longest. Unfortunately I did not at the time notice the forms of the tracts in these 

 birds, which I only once had the opportunity of examining. 



f>. Psittacula WAGL. P. puUarius possesses in its general arrangement precisely the 

 pterylosis of P. pcrtinax, but the tracts are much narrower and almost linear throughout. In 

 the inferior tract the biserial outer branch was certainly not divergent from the narrow main stem, 

 but indicated by stronger and closer feathers. The posterior portion of the dorsal tract forms a 

 weakly feathered fork, which, however, is not dilated externally, and its stem reaches from the 

 caudal pit to the distinctly existent oil-gland. There are no powder-down feathers. The wing 

 bears twenty remiges, of which the second is the longest. 



7. Platijcercus. Besides P. erythropterus, which I carefully examined, I have seen of this 

 genus P. novae seelandiae, P. pennantii, and some other species not accurately determined. The 

 first-named species exhibits a very remarkable narrowness of all the tracts, which were only two 

 feathers broad, but in other respects presents the forms proper to the Parrots, namely, the 

 double humeral tract, the furcate form of the hinder part of the dorsal tract, which is cleft as 

 far as the caudal pit, and the arms of which pass in between the stronger limbs of the anterior 

 part, the long lumbar tract, and the inferior tract divided before the middle of the neck. The 

 chief peculiarity of the Platycerci is also presented by this tract, namely, a complete and 

 perfectly (indeed, widely] divergent and ratlier stronger outer branch. The long, acute wings 

 consist of twenty-two remiges, of which the second is the longest; the oil-gland is present, 

 but there are no powder-down feathers. P. novae seelandice presents the same characters ; but the 

 more obliquely placed outer branch forms a hook at the end, and the fork of the posterior part of 

 the dorsal tract is somewhat dilated. Moreover, I only counted twenty remiges in the wings. 2 



8. Palceornis, WAGL. In this group also I overlooked the form of the tracts, and only 

 noticed that the two species investigated (P. alexandri and torquatus, BRISS.) possessed an oil- 

 gland, but no powder-down feathers. The number of remiges was from twenty-one to twenty- 

 three, and the second was the longest ; this, as also the first and third, has the inner half of the 

 vane narrowed towards the apex, and furnished with a slight angular emargination. 



1 It is remarkable that powder-down feathers occur only in those Parrots which are destitute of 

 the oil-gland, but not in all of these. 



The almost total absence of a furcula, which has already been referred to as a peculiarity of 

 many Parrots (P. mitratus, eximius, and galgulus) in Taylor's ' Phil. Mag./ 1831, No. 51, p. 232, occurs 

 as a general character of the Platycerci examined by me, and also in P. pullarius. This bone is 

 weak in all the Parrots. 



