THE PSITTACIN.E. 99 



seven rows of feathers, which are as wide apart as in Buceros (Plate VI, figs. 1, 2), 

 except that in the region of the outer branch the two outer longitudinal rows, for a 

 space of four transverse rows, are more closely approximated, and bear stronger feathers. 

 Towards the end of the sternum each band again becomes narrower, being at first four and 

 afterwards only three rows in width, by which means a broader, elliptical inferior space, reaching 

 to the anus, is produced between the two bands on the ventral surface. The inferior tracts also 

 terminate at the anus, after their coalescence with the equally sparse and nearly uniform 

 plumage of the thigh. The dorsal band issuing from the occiput presents very different 

 characters. It is from the first narrow, three feathers broad, and densely feathered. As far as 

 the shoulders it retains its linear form, and divides at this point into two narrow limbs, only two 

 feathers in width, but rather strong, which extend somewhat beyond the middle of the shoulder- 

 blades. Immediately between the extremities of these commences the second or covered portion 

 of the dorsal tract, in the form of two much more sparse, weaker, parallel bands of feathers, 

 containing only a single contour-feather in the first transverse row, two in the second, three in 

 the third, and so forth, until they have become so broad that their outermost very weak and 

 always sparser rows coalesce with the uniformly sparse plumage both of the thighs and crura. 

 In this way the two bands are continued to the caudal pit, after approaching and coming in 

 contact with each other from the middle of the pelvis. From this point a biserial band of 

 stronger and more closely approximated feathers runs through the homogeneous plumage of the 

 rump to terminate at the oil-gland, which is present in all the large Macaws. Besides these 

 tracts we observe only a simple, narrow, biserial humeral tract, which runs pretty exactly behind 

 the axillary cavity, and is connected anteriorly with the inferior tract. Powder-down feathers 

 are entirely deficient. In the wing I found twenty-three remiges, of which the third and 

 fourth are the longest. 



I believe I found precisely the same pterylosis in P. aracanga, ararauna, severus, militaris, 

 macavuanna, and carolinensis, WILS. ; indeed, it seems to occur in all true Macaws. P. caroli- 

 nensis alone differs from the larger South American species in having the cere covered with a 

 dense, satin-like plumage, twenty-one very long acute remiges, of which the second and third are 

 the longest, and in the complete absence of the oil-gland ; but it has exactly the sparse plumage 

 of P. macao ; indeed, the ventral portion of the inferior space was still narrower, and scarcely 

 wider than the naked band on the sharp edge of the crista sterni. 



On the other hand, the small South American Parrots with wedge-shaped tails, which 

 Wagler refers to Sittace, differ in several points from the Macaws. Of these I have most 

 carefully examined P. pertinax, the pterylosis of which is represented in Plate V, figs. 16 18. 

 It will be seen from the figures that the inferior tract divides higher up on the neck, that the 

 two pectoral bands leave a considerable portion of the surface bare as spaces, both in the middle 

 towards the sternal crest and externally on the trunk, and that the central or inferior space is as 

 wide on the breast as on the belly. To these characters may be .added the considerable 

 strengthening of the portion of the inferior tract representing the outer branch, which consists at 

 first of two and subsequently even of three rows of stronger feathers, and is somewhat divergent 

 at the end. The dorsal tract exhibits the following differences : it is separated, at least anteriorly, 

 from the long, biserial femoral tracts, and behind the caudal pit it consists merely of an undilated, 

 more densely feathered band. The most important circumstance, however, is the presence of 



