2l8 OUR SUMMER MIGRANTS. 



of the common Thick-knee, or Stone Curlew, 

 CEdicnemus crepitans, in some specimens of 

 which I have remarked a very distinct serration 

 of the middle claw, in others only the barest indi- 

 cation of it (the edge of the claw being very thin 

 and elongated) ; in others again no trace of it. 



The objections, however, which have been 

 taken to the suggested use of the pectinated 

 claw in the Nightjar, do not invalidate the 

 statements which have been made by Gilbert 

 White and other observers of the bird's move- 

 ments and habits, for the homologous structure 

 which is found to exist in certain species in no 

 way related to each other, may well be designed 

 for very different functions. 



I do not find in the works of either Macgilliv- 

 ray or Yarrell any mention made of the peculiar 

 viscous saliva which is secreted by this bird, 

 and which reminds one of what is observable in 

 the case of the Wryneck and the different species 

 of Woodpecker. It no doubt answers the same 

 purpose, namely, to secure more easily the strug- 

 gling insects upon which its existence depends. 



