ABYSSINIAN VINAGO. 203 



wing-covers, so that no specific distinctions can be 

 founded exclusively upon any one of these three 

 circumstances. On the other hand, the two birds 

 we have received from Senegal, although they agree 

 in their colours with those figured on the 276th 

 and 277th plate of Le Yaillant, differ most remark- 

 ably from each other in the size and general struc- 

 ture of their bills. Now, we do not remember a 

 single instance in the whole circle of ornithology 

 where such a variation takes place in the sexes of 

 one species. To illustrate this difference more 

 fully, we annex cuts 

 of the bills of both; 

 in that to which we 

 retain the old name 

 of Alyssinica-, the nos- 

 trils are placed close to 

 the base of the bill, so 

 that some of the frontal 

 feathers advance close 

 to the aperture, the 



base also is narrow and compressed : in our Vinago 

 nudirostriS) on the contrary, the aperture is placed 

 in the middle of the bill, half-way between the front 

 and the tip, while the basal portion is broad and 

 thick ; this structure is confirmed by two specimens, 

 in a very perfect state of preservation, now before 

 us, which precludes the supposition that the feathers 

 have fallen off at the base of the bill. We shall 

 now describe the colours and measurements of the 

 first of these species. 



