XXXI.–A List hf the Birds of the Anglo‐Egyptian Sudan, based on the Collections of Mr. A. L. Butler, Mr. A. Chapman and Capt,. H. Lynes, R.N., and Major Cuth‐bert Christy, R.A.M.C. (T.F.). Part IV. (concluded). Pelecanidæ–Struthionidæ