168 THE ZOOLOGIST. 



in different species. While discussing this characteristic and its 

 variability I may add that last spring I saw a Bean-Goose in 

 which the orange-coloured lipochrome of the bill had immersed 

 the otherwise white feathers at the base of the bill in such a manner 

 that this Goose possessed an orange-coloured feathered band 

 along the base of the upper mandible. 



The outline of the bill of the Bean-Goose is variable, but it 

 does not always vary in accordance with the diagnostic rules 

 of Mr. Frohawk. For instance, the culmen of the long-billed 

 specimens m and g is more convex than in any of the others, and 

 the short-billed specimen c has a rather strongly concave outline 

 of its culmen. 



The following table will facilitate the understanding of the 

 distribution of the five first-mentioned characteristics among 

 these twelve Bean-Geese, if "s" means " segeturri , '\\)s.e i "a" = 

 " arvensis "-like, and "i" = intermediate, with the letter between 

 parentheses indicating in which direction the variation tends to 

 go. The sixth characteristic is left out, as being rather arbitrary : 





a 



b c 



d e 



/ 9 



h i k I m 



1. 



<s 



<s <s 



s s 



i i 



i i a a >a 



2. 



<s* 



>s i 



i(s) i 



i(s) i 



i i(s) i(s) s s 



3. 



a 



i(a) i 



s i 



i i 



i(a) i(a) i(a) i(a) i(s) 



4. 



>s 



>S i(: 



>s) a . >a 



i(>s) a 



i(<a) a a >s a 



5. 



a 



i i 



i(a) i(s) 



s(i) i(s) 



s i i a(i) i 



From this table it may be seen that the intermediate charac- 

 teristics are most common, and that the others are distributed 

 in such a manner at both ends of the series, as well as in the 

 middle, that it seems quite impossible to divide the specimens 

 in two specific or even racial groups with the aid of these cha- 

 racteristics. I think accordingly that the conclusion may be 

 drawn from this comparison that it is impossible to maintain two 

 such species as Anser segetum and A. arvensis according to Mr. 

 Frohawk's definition, because there are to be found all kinds of 

 intergrading and connecting specimens. 



The great variability of the Geese has long been known, and 

 it is possible that the great variation found in these birds can 

 be explained partly by their habit of mating for lifetime (which 



* The nail larger, but the number expressing the relationship smaller, 

 than in " segetum," 



