51 G THE GANNET 



of the year, however, and even up to the age of sixteen 

 months, this pectination either does not exist, or is very 

 difficult to discern. Occasionally a second line of pecti- 

 nations may be detected, but then they are smaller, 

 and it may be they drop off, like the extremities of 

 the claws in Willow-Grouse. If these teeth have any 

 function at the present day it cannot be that of a 

 comb, because they are too close to one another to 

 serve such a purpose.* 



* The Australian Gannet, Sula serrator, and the African S. capensts 

 have just the same pectinations of the claw as S. hassana, while in 

 the Boobies the pectinations are even more pronounced. They are 

 very obvious in the Cormorant and Shag, but rudimentary in the 

 Pelican, and non-existent in the Tropic-birds and Frigate-bird. These 

 curious serrations exist in various birds, reaching their fullest de- 

 velopment in the Nightjar and the Bittern. Many plausible suggestions 

 have been made as to their proper fimctions, but none of them 

 satisfactory, and the only alternative conclusion which remains is 

 that their use, whatever it was, passed away in the ancestral times, 

 and has now become as obscure to us as the Archceopteryx' s tail ! 



