Birds from the White Nile. 465 
[I only saw one Lesser Black-backed Gull, near Ed-Duem. 
— H. M. H.] 
198. LiMNOCORAX NIGER. 
Limnocorax niger (Gmel.) ; Grant & Eeid, p. 694. 
a, b. c? et c? imm. Kaka, 7th May. Nos. 444 & 445. 
c, d. $ imm. Kaka, ISth April. 
Iris crimson; bill greenish chrome; upper portion o£ 
eyelid coral-red ; legs and feet dusky red, brighter at and 
above the tibio-tarsal joint. 
[I only saw a few individuals of the Black Rail. Several 
times I heard it utter its cry in the flags, but could not 
flush it. Mr. Loat kindly gave me two skins which he had 
procured. — R. M. H.] 
199. TURTUR DECIPIENS. 
Turtur decipiens Finsch & Hartl. Vog. Ost-Afr. p. 544 
(1870); Salvad. Cat. B. Brit. Mus. xxi. p. 420 (1893); 
N. C. Roths. & Wollast. p. 25. 
Turtur ambiguus Bocage, Orn. Angola, p. 386 (1877) ; 
Salvad. Cat. B. Brit. Mus. xxi. p. 419 (1893) ; Witherby, 
p. 266. 
a. S' Fashoda, 30th March. No. 255. 
b. S' EUKawa, 20th May. No. 525. 
c-e. S ? . Ed-Duem, 22nd May. Nos. 542, 543, 559. 
Iris yellow ; bill vinaceous ; legs and feet pinkish. 
I think there can be no doubt that 2\ decipiens and 
T. ambiguus are synonymous. Mr. Witherby and Messrs. 
Rothschild and Wollaston have pointed out certain differ- 
ences in the length of the wing and the width of the white 
tips to the tail-feathers, but, as will be seen by the following 
measurements, these characters appear to be sexual, not 
specific. 
The specimen from Argo Island, Dongola (one of the 
types of Columba collaris Hempr. & Ehr.), which Count 
Salvadori in the ' Catalogue of Birds ' refers to C. decipiens^ 
appears to me to be an unusually rufous specimen of the 
bird that he calls T. ambiguus. It is in worn plumage, and 
