This extensive and luxuriant district has only been explored zoologically in the neighbourhood of the West coast. Much, no doubt, remains to be done in the interior, yet its main features are sufficiently well known, and most of its characteristic types of animal life have, no doubt, been discovered. _Mammalia._--Several very important groups of mammals are peculiar to this sub-region. Most prominent are the great anthropoid apes--the gorilla and the chimpanzee--forming the genus _Troglodytes_; and monkeys of the genera _Myiopithecus_ and _Cercocebus_. Two remarkable forms of lemurs, _Perodicticus_ and _Arctocebus_, are also peculiar to West Africa. Among the Insectivora is _Potamogale_, a semi-aquatic animal, forming a distinct family; and three peculiar genera of civets (Viverridæ) have been described. _Hyomoschus_, a small, deer-like animal, belongs to the Tragulidæ, or chevrotains, a family otherwise {263}confined to the Oriental region; and in the squirrel family is a curious genus, _Anomalurus_, which resembles the flying squirrels of other parts of the world, without being directly allied to them. _Birds._--In this class we find a larger proportionate number of peculiar forms. _Hypergerus_ and _Alethe_, belonging to the Timaliidæ, or babblers, are perhaps allied to Malayan groups; _Parinia_, a peculiar form of tit, is found only in Prince's Island; _Ixonotus_ is an abundant and characteristic form of Pycnonotidæ; _Fraseria_, _Hypodes_, _Cuphopterus_, and _Chaunonotus_, are peculiar genera of shrikes; _Picathartes_ is one of the many strange forms of the crow family; _Cinnyricinclus_ is a peculiar genus of sun-birds; _Pholidornis_ is supposed to belong to the Oriental Dicæidæ, or flower-peckers; _Waldenia_ is a recently-described new form of swallow; _Ligurnus_, a finch, _Spermospiga_, a weaver bird, and _Onychognathus_ a starling, are also peculiar West African genera. Coming to the Picariæ we have _Verreauxia_, a peculiar woodpecker; three peculiar genera of barbets (Megalæmidæ); the typical plantain-eaters (Musophaga); _Myioceyx_, a peculiar genus of kingfishers; while _Berenicornis_ is a genus of crested hornbills, only found elsewhere in Malaya. The grey parrots, of the genus _Psittacus_, are confined to this sub-region, as are two peculiar genera of partridges, and three of guinea-fowl. We have also here a species of _Pitta_, one of the Oriental family of ground-thrushes; and the Oriental paroquets, _Palæornis_, are found here as well as in Abyssinia and the Mascarene Islands.