164 ANIMAL SKETCHES. CHAP. 



gulls this hind toe is fast disappearing. In the kittiwake 

 it has well-nigh gone. Almost suppressed in the black 

 foot of the guillemot, it has quite gone from the dainty 

 orange feet with sharp, black, curved claws of the puffin. 

 In other swimmers, however, the hind toe is of fair size, 

 and a membrane joins it with the next toe so that the foot 

 is completely webbed, as in the green-toed, dusky-webbed 

 foot of the gannet, the long, black paddle of the cormorant, 

 or the foot of the pelican which you may see in the Zoo. 

 Lastly, in those excellent swimmers and divers the grebes, 

 of which our little dab-chick is an example, instead of the 

 foot being webbed in the ordinary orthodox fashion, each 

 toe is flattened out by lateral extension of the scales 

 which cover it. Even the claws or nails are beautifully 

 flattened, and the little hind toe has a similar form. 

 When the propelling stroke of the foot is given the toes 

 spread out and give a broad, three-lobed surface; but 

 when the foot is drawn forward in recovery for a fresh 

 stroke, the toes fold together flatly and overlap one behind 

 another in such a way as to cut through the water like a 

 knife. Nothing can be more admirable than their exquisite 

 mechanism for feathering. The foot of the bald-headed 

 coot, which (with his more abundant cousin the moor-hen, 

 nodding its head and flicking its tail to show the white 

 under-coverts) we all know on our rivers and lakes, is 

 lobed in a somewhat analogous way, but not with so 

 perfect a finish as in the grebe. Indeed the grebe is an 

 ideal swimmer and diver. His sharp little head, his 

 smooth neck, his oval or spindle-shaped body, with only 

 a lame apology for a tail, and his admirable propelling 

 feet thrown as far back as possible all bespeak a bird in 

 which habit and structure are in most excellent coadapta- 

 tion. 



It is through their knowledge of these coadaptations of 



