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and form have been infused frequently. In the Common Goose 

 some of them are so like the original species in all apparent re- 

 spects, that I cannot fancy why it should ever have been supposed 

 they have any trace of either the White-fronted or any other 

 species. It always strikes me as carious why the various spe- 

 cies, taking all known into account, do not differ from one ano- 

 ther in a more equal degree. We find two very nearly allied, 

 then we have to look some distance ; we then find perhaps several, 

 then again there is a wide gap in the chain, and so on. I do not 

 wish to be understood that we should expect to find one species 

 so like another that a regular arrangement could be made ; that 

 is quite impossible, as one species sometimes resembles another 

 in one respect, while in others it resembles other species again 

 further off ; but, for instance, if the American Wigeon and Teal 

 are different species from the European, where is the next spe- 

 cies on either side of either of them connecting either of them as 

 closely to any other species ? C. M. A. 



