790 Messrs. Selater and Mackworth-Praed on [ Ibis, Mesophoyx intermedius brachyrhynchus.

Herodias [Egretta| brachyrhynchos Brehm, J.f.O. 1858, p. 471: Blue Nile.

Herodias brachyrhyncha Reichw. V. A. 1. p. 389; Butler, Ibis, 1905, p. 372, 1908, p. 200.

Recorded by Heuglin from Kordofan and the White and Blue Niles. There are specimens in the Museum from the Sobat River.

Demigretta schistacea.

Ardea(Lepterodias) schistacea Hempr. & Ehr. Symb. Phys., Zool. ii. 1828, fol. i. pl. 6: Northern Red Sea.

Herodias schistacea Reichw. V. A. 1. p. 387.

[C. & L. coll.] 2 Port Sudan Dec. & Apl. B.S. One of these birds is in grey plumage changing to white, the other in almost complete white dress. This bird has a long tarsus, and is appareutly quite distinct from D. gularis from the rest of Africa, which also does not appear ever to have a white phase. Nor do these birds seem to us to be the same as the Indian form (Ardea asha Sykes, P. Z.S.

1882, p. 157: Deccan), in which the grey phase is considerably paler. We do not think, however, that there are sufficient grounds to justify its separation from the genus Demigretta. We cannot say from present material whether this species has two dimorphic forms—a grey and a white— or whether one is the young of the other. Hemprich and Ehrenberg concluded that the white form was the young one, and this may prove to be the case ; but what we have little doubt of is that, unlike the Australian Reef-Herons (ef. Mathews, Birds of Australia, i11. p. 454), these are both forms of the same species. We can trace no record of the true LD. gularis (Ardea gularis Bosc, Actes de la Soe. d’Hist. Nat. Paris, i. 1792, p. 4, pl. 2: Senegal River) ever having occurred in the Sudan, the specimen labelled “ Nile” (Sir F. Galton) mentioned in the British Museum Catalogue being an undoubted example of D. schistacea, and the older authors not having separated the two birds. ‘This species appears to be an almost exclusively marine form, while D. gularis is also an laud form.