526 
Mil MACGILLIVRAY ON 
thologicus of Latham. That this also may not be 
thought deficient in proof, T shall adduce an example : 
Gmelin. Latham. 
Falco cyaneus. Falco cyaneus. 
bohemicus. europhigistus. 
albicans. griseus. 
pygargus. pygargiis. 
griseus. riibiginosus. 
montanus. ranivoras. 
— hiidsonius^ 
Buffonii. 
And not only has this adherence to colour produced divi- 
sions in identical species, but it has even induced systematic 
authors to place at wide distances from each other animals 
of precisely the same specific form. Nothing can more dis- 
play our want of real knowledge in ornithology than this : 
it is surely little calculated to make us proud of our ac- 
quirements, when, on determining two birds to be of the 
same species, we turn to our systematic arrangements, and 
^ind these two birds not placed the one after the other, as 
their natural identity would lead us to expect them, but 
with the intervention of half a dozen or more species. The 
Falco Alhicilla and ossifragus are of this description, and 
many others, which it is unnecessary and would be tedious 
to enumerate. Characters, therefore, derived from coloiu*, 
are not sufficiently distinctive. 
The comparative length of the tail, of the wings, and 
still more of the tarsus and middle toe, are also cliaracters 
in use ; but these, at least the two first, cannot be of gene- 
ral application, being only capable of being used occasion- 
ally as a specific character, and more frequently as a divi- 
sional one. The latter of these modes I camiot imaoine to 
o 
be of the most trifling utility : it affords no positive cha- 
