FOSSIL BIRDS. 165 



The inter-resemblances of birds are considerably greater 

 than those of quadrupeds. The extreme limits of the class 

 are more approximated to each other, and the number 

 of species contained within those limits is much more con- 

 siderable. The differences, therefore, between two species 

 must at times be utterly impossible to decide, on inspection of 

 the skeletons. Even the genera do not always possess osteo- 

 logical characters of a sufficiently discriminative importance; 

 They are almost all distinguished according to the form of 

 the bill, which is not preserved entire in the ordinary 

 skeleton, and still less so in the fossils, crushed and fractured 

 as they have been in the gypsum of Paris. All, therefore, that 

 can be said on the specific characters of ornitholites amounts 

 to little, and scarcely passes the bounds of mere conjecture. 



It is, however, certain that the number of complete feet 

 found in the gypsum furnishes proof of the existence of at 

 least nine species, which M. Cuvier has arranged according to 

 size, beginning with the largest and ending with the least. The 

 other skeletons and fragments he refers to certain of these feet, as 

 belonging to those species, with the exception of the skeleton of 

 M. Darcet. To this skeleton there are no feet, nor any portions 

 of feet remaining ; but as the wings and neck are shorter than 

 those of the skeletons above cited, and as in those two the first 

 is smaller than any found, the Baron concludes this bird to 

 have been of a different species from all the others, and to have 

 constituted a tenth. 



Several feet and bones, not referable to the skeletons we 

 have mentioned, have been found, nor in all instances refer- 

 able to the feet which we have noticed as designating distinct 

 species. 



A shoulder-blade was found, resembling that of the genus 

 pelican ; a foot resembUng that of the sea-lark ; a metacarpus 

 of a bird of prey, of the magnitude of Faico haliaetos, and 

 which M. Cuvier thinks may indicate an eleventh species : 

 there was also a femur which had the strongest resemblance 



