INTRODUCTION. 101 



the turraccos; the violet species (Musophaga mo- 

 lacea) has ever been a favourite bird with orni- 

 thologists, and it is more frequently met with in the 

 forests of Senegal than on the Guinea Coast, where 

 M. Isert, its first describer, mentions it as parti- 

 cularly rare ; besides the two species of this group 

 which we actually know to be natives of this coast, 

 there are two others which authors describe as 

 likewise natives of Senegal. 



The existence of at least three species of halcyon, 

 where not one is found, as we believe, in Southern 

 Africa, proves that the distribution of these forest 

 king-fishers, or rather crab-eaters, are distributed 

 in a lateral direction within a certain distance on 

 each side of the equator. The only exceptions 

 being two or three species found in Australia. 



Of the gallinaceous or rasorial birds little can 

 be said. Western Africa appears the metropolis of 

 the Guinea fowls, and our list contains a species 

 apparently new. There are, no doubt, on the 

 sandy districts, several other species of land-grouse 

 (Pterocles) and of partridges, than those few which 

 have yet come to our hands. 



The mouth of the river Gambia is frequented by 

 several aquatic birds, which will be more particularly 

 noticed in another volume. 



Having now, by this rapid sketch, sufficiently 

 prepared the reader for entering into the details of 

 this volume, we shall at once proceed to describe 

 the subjects themselves. 



It will hardly be necessary to inform the orni- 



