OBSERVATIONS ON THE GANNET. 193 



many other birds, at least those observed by me 

 had nothing remarkable to substantiate a charac- 

 ter. From personal experience, I can aver, that 

 two or three species are sometimes found to infest 

 the same subject, and that one or other of these 

 has also been found on others. There is every 

 reason to believe, that the pediculus of the magpie 

 is found on some of the duck tribe, and the very 

 long and slender pediculus, of the Cinereous eagle, 

 has been taken from the black martin, so that this 

 class of insects may be extended without limits, 

 and without benefit to science, unless specific di- 

 stinctions can be clearly defined. 



