European, and hair that is in curly ringlets. Their gradual invasion of the Western Sahara, Nigeria, and Senegambia—in the south they reached down to the Lower Niger and Yoruba-land, to Baghirmi, and across the Benue to within a few days’ journey of the Cameroons coast—may have been caused by the peopling of North Africa some ten or more thousand years ago by the Libyans or Berbers, a Caucasian people related in speech and origin to the Gala and other Hamites of N.E. Africa, and to the ancient Egyptians. Four other negroid peoples require to be considered in their effect on the colonization of Africa before we can deal with the more clearly alien races. These are the Songhai of Central Nigeria, the Mandingo of Western Nigeria, the Hausa, and the Tibus or Teda. The Songhai (Sughai, Songhoi—the _gh_ is like the French _r_ _grasséyé_) are something like the Wolofs in appearance, in that, though black-skinned and woolly-haired, their features are often of Caucasian cast, and their characteristics generally those of negroids rather than negroes. Their language (the common speech of Timbuktu) is at present an unsolved mystery, its affinities are unguessed at. The Songhai seem to have dwelt first (where they still live under Tuareg influence) in the Oasis of Agades, a country on the southern verge of the Sahara, due east of the great Niger bend. Here they appear to have received immigrants from Ptolemaic or Roman Egypt, who brought with them Egyptian domestic animals and the Egyptian style of architecture. This last they applied to building in mud instead of stone. But, although much modified since by Berber or Arab (Saracenic) influence from the north, this massive Egyptian style of mud-built walls, palaces, and mosques still prevails throughout northern Nigeria from the Upper Niger to the vicinity of the Shari River.