82 Mr. jfoJui Flower. 



ig. — On the Peculiar Shape of the Claw of the 

 Middle Toe of Birds. 



By the President. 



[Read December i^th, 1880.] 



The pecuharly serrated shape of the claw of the middle toe 

 of the Nightjar (C. Europoeus) is well known, and many are 

 the ingenious theories which have been framed to account for 

 its peculiar form. The claw of the middle toe is also serrated 

 in the Herons and Cormorants, and in other birds peculiarities 

 in this claw have been noticed. It is not, however, my inten- 

 tion now to go through these in detail, or to endeavour to 

 explain the reason for their peculiarities. I propose on the 

 present occasion merely to point out a matter of some interest, 

 which seems to throw some light upon the peculiarities to 

 which I have referred. 



The number of birds in which peculiarities in the claw of 

 the middle toe have been noticed and described is compara- 

 tively small, and it is somewhat singular that all naturalists 

 who have dealt with this subject have describdd these cases as 

 something altogether exceptional, as if, in fact, they were the 

 only birds in which this claw is different from the others. 

 I believe, however, that a close and exhaustive examination of 

 the feet of birds would show that there are very few, if any, 

 birds in which the claw ot the middle toe is not more or less 

 modified in form. The outside edge of this claw, as a rule, is 

 not peculiar, but the inside edge is so far modified that it is 

 easy to tell whether any particular foot is a right foot or a left 

 foot by this peculiarity alone. 



The series of birds' feet which I have here, aud which com- 

 prise numerous examples from each of the five orders into 

 which British birds are divided, will make this very clear. In 

 all of them the inside edge of the middle claw is much developed 

 and altered in shape. 



It would be dangerous to attempt to frame a theory to 

 account for this peculiarity until the matter has been more 

 fully considered and investigated, but I hope our members will 

 not lose sight of this subject, and if any remarkable modifica- 

 tion of this claw should come under their observation they 

 should not fail to bring it forward at one of our meetings. 



