Europe to Mongolia, | | | N. Africa | ANSERES. | | | ANATIDÆ. | | | | | | Aix | 1 |N. China to Amoor |N. America Bucephala | 3 |Iceland, N. Europe, and|N. America | | Asia | Histrionicus | 1 |Iceland, N. Siberia |N. America Harelda | 1 |North of whole region |Arctic America Somateria | 3 |North of whole region |N. America Oedemia | 3 |North of whole region |N. America | | | LARIDÆ. | | | | | | Rissa | 1 |North coasts of whole |N. America | | region | | | | COLYMBIDÆ. | | | | | | Colymbus | 3 |North of whole region |N. America | | | ALCIDÆ. | | | | | | Alca | 2 |North coasts of whole |N. America | | region | Fratercula | 3 |North coasts of whole |N. America | | region | Uria | 3 |North coasts of whole |N. America | | region | Mergulus | 1 |Iceland and Arctic |Arctic America | | coasts | --------------------+-----+-----------------------+---------------------- [Illustration: ETHIOPIAN REGION] {251}CHAPTER XI. THE ETHIOPIAN REGION. This is one of the best defined of the great zoological regions, consisting of tropical and South Africa, to which must be added tropical Arabia, Madagascar, and a few other islands, all popularly known as African. Some naturalists would extend the region northwards to the Atlas Mountains and include the whole of the Sahara; but the animal life of the northern part of that great desert seems more akin to the Palæarctic fauna of North Africa. The Sahara is really a debatable land which has been peopled from both regions; and until we know more of the natural history of the great plateaus which rise like islands in the waste of sand, it will be safer to make the provisional boundary line at or near the tropic, thus giving the northern half to the Palæarctic, the southern to the Ethiopian region. The same line may be continued across Arabia.