CEREBRAL DEVELOPMENT OF BIRDS. 89 



in his atlas, upon the skull of a mallard, the organ of Lo- 

 cality, as occupying the whole extent of the frontal bone, 

 the seat of, according to Vimont, at least seven or eight 

 distinct organs. 



Vimont next proceeds to apply his doctrines as follows : 

 The frontal bone of birds, says he, may present two very 

 different characters in its anterior and external portion, or 

 that which forms an arch over the orbits ; it may either be 

 depressed and flattened, or else present a considerable de- 

 gree of swelling, The first arrangement is seen in the 

 raven, magpie, cuckow, the swift, and the different species 

 of herons. In ducks, again, wild-geese, and swans, the 

 orbitar border is rounded and swelled, as if pushed out 

 from within. In all those species of the above which have 

 the orbitar border, we are to look for the organ of Locality 

 further back. It is easy to see, he continues, that this part 

 is sensibly prominent on the skull of the swallow, the swift, 

 the cuckow, and indeed of all summer birds of passage. 

 In several winter visitants, again, as all the geese and 

 ducks, the orbitar border is rounded and arched. This 

 conformation Vimont considers to be owing to the large 

 size of the organ of Geometry, because these birds fly in 

 triangles. This organ is large also in the grebes, curlews, 

 and godwits. None of the summer birds, again, have this 

 arrangement. 



Such, then, is the body of facts on w hich Vimont trium- 

 phantly rests his theory of the migration of birds. But a 

 very few words will suffice to expose the fallacy of his mode 

 of inquiry, and to point out the opposite results to which 

 another person may come, who has no favourite hypothesis 



