The extension of irrigated crops can only be made in the vicinity of the larger rivers, or where good wells exist, and it may be found more expedient, therefore, that the inhabitants of the Niger, Benue, Kaduna, Gongola, and Gurara valleys should be urged to cultivate rice and maize under these conditions. The use of the land for two crops in each year would be made possible by the introduction of a leguminous crop as an intermediate, being sown later but in the same field with the irrigated crop, and being permitted to ripen, after the grain has been harvested, upon the stubble. A leguminous grain suitable for human food would be necessary in the river valleys where cattle are scarce, but a cattle food could be grown in the north where cattle are common, and where milk forms an important article of human consumption. =GUINEA CORN= (_Sorghum vulgare_)—“Dawa” (Haussa), otherwise known as the Great or Indian Millet “Juar” (Hindustani), “Dhura” (Egyptian)—forms the most important food-grain of the inhabitants of the ultra-forest region of West Africa. A large number of different varieties are recognised in Northern Nigeria, and are distinguished in the manner stated below. Most of these have a grain which is commonly used for human food, but at least two varieties are grown for other purposes. The following list states the characters by which the various kinds can be determined from the appearance of the seed and form of the stem. 1. “Asidinono.”—Seed with white shell and black adherent envelope. 2. “Farafara.”—Seed with white shell and red adherent envelope. 3. “Boganderi.”—Seed with straw-coloured shell and red adherent envelope. 4. “Janari.”—Seed with pink shell and red adherent envelope. 5. “Kaura-ferin-sosia.”—Seed with straw-coloured shell and straw-coloured adherent envelope. 6. “Bokin-sosia.”—Seed with straw-coloured shell and black adherent envelope. 7. “Makafo-dewayo.”—Seed with straw-coloured shell and pointed straw-coloured adherent envelope, which scarcely opens. 8. “Asidigero.”—Small pink-shelled seed with red adherent envelope. 9. “Mazgua.”—Very large whitish seed with a straw-coloured envelope. 10. “Karandeffi.”—Seed with red shell and red adherent envelope. Never used for food, but employed in native medicine, as well as for the production of the red dye used for leather (_Bull. Imp. Inst._, vol. vi. [1908]). 11. “Takanda” or “Karantalaka.”—The seed has not been examined, but the stem contains a large quantity of saccharine juice, and the plant is grown entirely as a cattle food. Probably identical with _S. saccharum_.