40 JOURNAL, BOMBAY NATURAL 1 HISTORY SOCIETY, Vol. XVII. 



parts, are best taken from the figures : the eye should suffice for this. 

 The height at the forehead ; the greatest depth of the lower mandible ; 

 the curve or outline of the edge of the lower mandible ; and the depth 

 of the bill just behind the nail are the chief points to observe. I 

 believe that this side-view, or elevation of the bill as it may be termed, 

 is the only character of any real value. 



Other characters in these Geese to which importance is sometimes 

 * attached, are entirely fallacious, and obscure what is otherwise quite 

 simple. The colour of the plumage is useless, for all the species are 

 so similarly plumaged that the existing slight differences cannot be 

 made out without actual comparison of specimens, and even then 

 there is not much to be made of it. Size is also of doubtful value, unless 

 the bird is sexed, for the males of the smaller species approach in size 

 the females or younger males of the larger species. When the bird 

 is sexed, size, as shewn by the length of the wing, is no doubt of some, 

 but not of extreme, value. It merely serves to corroborate the identi- 

 fication from the bill. 



Then there are other characters of the bill which many writers harp 

 Upon and think of great importance. First, there is the colour of the 

 bill. The black portion always remains black, but the pale portion, he 

 it orange or some shade of red, soon after death, becomes of a dingy 

 yellow colour. It is obvious, therefore, that the colour of the bill 

 cannot be of any use. It may be recorded on a label and it is no 

 doubt satisfactory to know how the bill of a specimen was coloured 

 in life; yet the fact remains that birds must, as a rule, be studied 

 and identified as dry skins, and consequently the colour of the bill, 

 though interesting to be known, cannot be treated as a character of 

 value. 



Secondly, there is the amount of and the distribution of the two 

 colours on the bill of a Bean-Goose, the black and the pale colour. 

 The proportion of each of these varies with age. Generally speaking, 

 the younger birds have merely a ring or zone of pale colour behind the 

 nail. With increasing age, some of the black disappears and is re- 

 placed by the pale colour under the nostrils and along the edges of the 

 upper mandible ; and in an extreme case, such as A. arvensis, the pale 

 colour occupies nearly the whole bill in very old birds. It is plain that 

 the distribution of the two colours on the bill cannot be made of any 

 practical value. 



