78 NOVITATES ZOOLOGICAE XXVIII. 1921. CAPTAIN ANGUS BUCHANANS AIR EXPEDITION. IV. THE BIRDS COLLECTED BY CAPT. ANGUS BUCHANAN DURING HIS JOURNEY FROM KANO TO AIR OR ASBEN. By dr. ERNST HARTERT. (Plates I.-IX.) THE best zoogeographical boiindarj', apart from vast oceans, has hitherto been the Sahara, a wide belt of poorly inhabited and unexplored country. As long as we knew very little about it, this was a very simple question — north of the Sahara palaearctic, south of it aethiopian. This contention, however, was bound to be shaken to some extent when the Sahara (as it is marked on maps) became zoologically explored. Until the second decade of this century the Great Desert had only been touched by zoological collectors on some of its borders : in the east near the Nile, in the north from Algeria, Tunisia, and Tripoli-tania. South of Algeria the Koenigs had collected as far as Ouargla, Erlanger and Spatz from Tunisia about as far or little more to the south ; Whitaker's intrepid collector, Dodson, had penetrated as far as ^Murzuk in Fezzan, south of Tripolitania, and his collections added much to our knowledge, but were evidently not exhaustive. J. Dybowski had collected during his inspecting-toiu-to El-Golea, but of the 42 species of birds which he brought home very few came actually from El-Golea, but were taken all along the route from Ghardaia to El-Golea, and mostly not properly labelled. Riggenbach collected a few birds at the Rio de Oro and Comte de Dalmas at the Bale de Levrier, Cap Blanco south, but neither of these latter travellers had penetrated into the interior, and each had only obtained a few specimens. • In 1912 I collected industriously, accompanied by Hilgert, as far south as Tidikelt (In-Salah), and in the same year Spatz and Fromholz collected as far as Temassinin. In 1914 GejT von Schweppenburg and Spatz made their fruitful expedition to Ideles, on the slopes of the Hoggar Mountains. Thus some know-ledge was obtained of the Saharan avifauna, but its greater part remained still unknown — not a step had been made (by ornithological collectors) into the desert south of Marocco and north of the Senegal, the central belt remained unknown almost from the Nile to the Atlantic. Looking at any map, a somewhat large mountain-land. Air or Asben, catches the eye in the middle of the Sahara, on older maps and in textbooks called an " oasis," which is, however, a most misleading name for a mountainous country with desert tracts and valleys, towns and villages, mountains rising up to about 2,000 m. in height. Zoologically Air remained absolutely unlcnown until Buchanan's expedition. It was with great satisfaction to myself that Lord Rotlischild fell in with my
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