THE VICTORIAN NATURALIST. 177 



parallel case to a P. adelaidm I am about to mention. In P. 

 nigrescens the plumage is in many parts very black, which leads 

 me to think it is a rare case of Australian melanism, especially 

 as in one specimen the black overpowers the greater part of the 

 blue cheeks. Very few specimens are known. 



500. Platycercus adelaid^e, Gould, Adelaide Rosella. 



The key given to this species by the British Museum in 1891 

 is — " Cheeks blue ; under parts pale red, each feather slightly 

 fringed with yellowish." 



The key given by Dr. Ramsay, " Catalogue Aust. Museum, 

 Psittaci," 1891, is for the female — "Cheeks blue ; the feathers of 

 the under surface of the body dull yellow, washed with red at 

 their tips." 



The key to my specimen is — " Cheeks blue ; under parts have 

 some of the feathers quite red, others quite yellow, and a few 

 subterminally edged with light violet, all irregularly disposed, 

 while across the forehead is a band of red." 



The key to P. elegans is — " Cheeks blue ; under parts 

 crimson." 



I am quite satisfied that this particular bird to which I wish 

 to draw your attention is an abnormal form of P. adelaidm, as 

 its plumage appears to be half male and half female, but I am 

 not sure that P. adelaidce is a distinct species from P. elegans 

 [pennantii). I am rather inclined to think that the first three 

 types are all tending to Xanthochroism, and that my specimen is 

 the most successful. Possibly it is the reversional step observed 

 in parrots by Meyer in 1882. 



Comparing my specimen with an adult of P. elegans, instead 

 of the whole ventral surface being uniform red there is a 

 tendency to nondescript yellow, with red blotchings on the chest, 

 and the same, but rather more pronounced, on the abdomen. 

 The dorsal appearance of red with dense black and deep scale 

 markings in the normal bird is replaced by a general appearance 

 of black with faint red and dirty yellow " scales " or edgings to 

 the black feathers. But the marked peculiarity of this specimen 

 is that some of the crimson edgings to each feather are replaced 

 by muddy yellow on the interramal region and faint red on the 

 lumbar, thus resembling P. adelaidm. Across the forehead is a 

 band of crimson. On the crown, nape, neck, and sides of the 

 head the clear crimson of the normal adult gives place to dirty 

 yellow, fused in parts with an orange red, while the deep and 

 light blues on the cheeks, wings, and tail are as strong as in a 

 mature bird. In development from youth to age P. elegans has 

 several stages, and necessarily it takes some years to attain " full 

 feather." This extraordinary specimen was doubtless under- 

 marked by green and yellow in its first two years, and then as 



