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. 



FAMILY GALLINULID.E. 



Nearly allied to Rallidse, but comprising forms developing frontal shields 

 and more or less swimming habits. Probably comprising most extinct semi -flightless 

 " Rails." A semi -flightless form, Tribonyx, 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 Microtribonyx 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 Tribonyx 

 evolved through isolation and indolence ; on the continent Microtribonyx developed 

 but competition allowed it no rest to induce Sightlessness ; 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 Mantdlornis, a parallel case with the Australian Porphyrio. 

 Many extinct forms have followed the same course. 



Genus AMAURORNIS. 



Amaurornis Reichenbach, Nat. Syst. Vogel, p. xxi., 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 culmen. 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. 1st: Amboyna. 

 Extra-limital.] 



Gould, Suppl., pi. 79 (pt. v.), Aug. 1st, 1869. Mathews, Vol. I., pt. 4, pi. 58, Aug. 9th, 1911. 



