168 MR. W. A. FORBKS ON THE GENUS LATHAMUS. [Feb. 18, 



results of my inquiries before the Society to-iiigbt, in order to 

 establish the view that Lathamus must be removed from the brush- 

 toiigued Trichoglossinoi, with which it has been so generally asso- 

 ciated, and must be considered a (no doubt aberrant) member of the 

 Platycercine group. 



The pterylosis of this form having first struck my attention, I 

 will describe this in the first instance, the more so as, as far as I 

 know, no description of this part of the structure of the bird in 

 question has yet been pubhshed. I may perhaps anticipate part of 

 my paper on the pterylosis of the Psittaci in general, and point out 

 briefly the general characters of the distribution of the feathering in 

 these birds, so as to enable the reader without any further trouble to 

 appreciate the points of distinction in this respect between Lathamus 

 and the other species with which I have compared it. 



As will be evident from the figures (PI. XVT. figs. 1-6), the 

 tracts of contour-feathers in a Parrot may be arranged as follows : — 

 On the upper surface of the body, continuous in front with the 

 feathering of the top and sides of the head, is a long narrow tract, 

 the " superior tract," which divides behind in the interscapular region 

 in a fork-like manner, forming the " scapular fork." Behind this, 

 occupying the hinder part of the back and pelvis, is another, more 

 or less Y-shaped tract, with the "handle" (which is usually short) 

 of the fork placed close to the posterior extremity of the trunk, 

 whilst the more lengthy " arms " of the Y are more anterior, and 

 run in, in front, between the corresponding ones of the " scapular 

 fork," usually becoming very feebly feathered in so doing. This 

 tract may be called the " dorso-lumbar " fork. Scattered more 

 irregularly and diffusely over the sides of the pelvis, and external to 

 the last-named tract, is the "lumbar feathering," which passes 

 posteriorly on each side into the narrower but more distinct " femoral 

 tracts." These are continued onto the legs as far as the tarsi as 

 the " crural tracts," clothing the legs in a trouser-like way. On the 

 inferior surface, on each side, is a continuous tract, running from 

 the upper part of the neck (where it may or may not unite with its 

 fellow of the opposite side), over the breast and abdomen, to the 

 anus. This " inferior tract," besides one or two small branches 

 running towards the humerus and patagium (the first and second 

 "humeral tracts"), gives off, at about the commencement of the 

 sternum, a more or less separate and well-marked external branch, 

 the " outer pectoral " tract, which runs down more or less parallel 

 to the main part of the inferior tract for a little way, but ceases before 

 the thighs. 



Amongst the various species of Psittaci I have examined, well- 

 marked differences in some of these tracts occur, more particularly 

 in the arrangement of the "dorso-lumbar fork," and the jireater or 

 lesser development of a distinct " outer pectoral " branch to the 

 inferior tract. 



In Lathamus discolor {VX.Hyi. figs. 1, 2), the inferior tract of each 

 side starts from about the angle of the jaw, and does not unite with 

 its fellow. On the sternum it is about eight or nine feathers broad at 



