134 WHITE BACKED CROW. 



over. Whenever a wide difference of geographic 

 range is accompanied by others of colour, we may 

 generally assume that species having some simi- 

 larity are nevertheless distinct. 



These observations are applicable to the present 

 bird. It has much resemblance to that figured by 

 Le Yaillant under the name of Le Corneille a sea- 

 pulaire Uanc (Ois. d'Af. ii. PI. 53.J, from the 

 southern extremity of this continent ; but if it were 

 the same, we can hardly suppose he would have 

 represented the bird as having the black extending 

 no further than the chin, when in this it occupies the 

 whole of the neck and breast. Until, therefore, 

 we have further evidence upon this point, we ven- 

 ture to consider the Senegal bird as distinct. The 

 black part of the plumage is very glossy ; and the 

 feathers of the head and throat are pointed. The 

 wings are very long, and reach to the end of the 

 tail; this latter is rounded, having the feathers 

 yery broad and mucronate. 



The form is strictly typical. Total length, about 

 18 inches; bill, from the gape, 2^ 2 5 ; wings, .13^; 

 tail, 7 ; tarsus, 2. 



