RUFOUS-TAILED MOORHEN. 203. 
and short secondaries ; P. c. parryi (Mathews) from North-west Australia, still darker 
as to head, back, thighs and under tail-coverts ; P. c. brevipes (Ingram) from the 
Bonin Group, with lower flanks and under tail-coverts more rufous, lower back more 
ruddy, a deeper bill and smaller feet, tarsus 32 mm., middle toe 33 mm. against 
typical tarsus 36 mm., middle toe 39 mm. ; P. c. ocularis (Ingram) from the Philip- 
pines, especially on the head, purer olive-black and grey neck and greyer breast ; 
P..c. tannensis (Forster) for birds from Fiji and Samoa, with more ruddy back and with 
little grey wash on head and none on neck; and P. c. ingrami Brasil from New 
Caledonia, with a small delicate bill, culmen 19 mm. long by 7 mm. high, against the 
preceding 22.5 by 8.5 mm. 
Famity GALLINULIDA. 
Nearly allied to Rallide, but comprising forms developing frontal shields. 
and more or less swimming habits. Probably comprising most extinct semi-flightless 
“ Rails.” A semi-flightless form, T'ribonyx, native of Tasmania, is obviously only a. 
degenerate island form of the mainland Microtribonyx, which is just as surely the 
unchanged representative of the well distributed Gallinula, the immature of the 
last named showing the bill coloration of Tribonyx. That genus has left the water 
and is more a land bird and the toes are comparatively short, while in the swimming 
Gallinula the toes are long. The mainland Microtribonyz is also a land bird and the 
sequence seems exactly parallel to that of many other Australian birds. In the 
times when Australia and Tasmania were joined, the ancestral form of Gallinula 
arrived and populated the country ; then Tasmania was severed and T'ribonyx 
evolved through isolation and indolence ; on the continent Microtribonyx developed 
but competition allowed it no rest to induce flightlessness ; at a later period the 
stronger, more powerfully constructed Gallinula arrived to oust the stationary 
Microtribonyx which it has not yet done, and thus we have a tableau of the struggle 
for existence in present view. In New Zealand we see a further stage in the present 
almost extinction of Mantellornis, a parallel case with the Australian Porphyrio. 
Many extinct forms have followed the same course. 
Genus AMAURORNIS. 
Amaurornis Reichenbach, Nat. Syst. Végel, p. xx1I., 1852 (? 1853). Type (by original 
designation) : Gallinula olivacea Meyen. 
Small Moorhens with long stout bill with small frontal plate, short wings, 
short tails and long legs with short (for this group) toes. 
The bill agrees in detail with that of Tomirdus, save that it is a little larger 
and stronger and has developed a frontal plate at the base of the cuimen. In this 
genus this is scarcely seen until the bird is adult. The wing is short and rounded, 
the feathers strong, the first primary short, the second and fifth subequal and little 
less than the third and fourth which are longest ; the inner secondaries are long. 
The tail is short and rounded, much less than half the length of the wing, the feathers 
broad and soft. The legs are long, the tibia unfeathered for about one-third the 
length of the tarsus, and like that, scutellated in front and behind ; the toes are 
long but less than the tarsus in length ; hind-toe very long and lateral membranes 
to toes little developed. 
Coloration brown above, slaty-grey below, under tail-coverts rufous. 
140. Amaurornis moluccanus.—RUFOUS-TAILED MOORHEN. 
[Porzana moluccana Wallace, Proc. Zool. Soc. (Lond.), 1865, p. 480, Oct. Ist: Amboyna. 
Extra-limital.] 
Gould, Suppl., pl. 79 (pt. v.), Aug. Ist, 1869. Mathews, Vol. I., pt. 4, pl. 58, Aug. 9th, 1911. 
