front, so that in the action of swimming, very 

 little velocity is lost in bringing the leg forward. 

 All these birds are web-footed ; but mark how 

 different is the web in different species, and how 

 each has its foot adapted to its mode of life. 

 The gulls and terns, which seek their food upon 

 the surface of the water, and cannot dive, have 

 the back toe very small, and unconnected with 

 the others ; while in the cormorant, which seeks 

 its prey beneath the water, we find the back toe 

 very long, and connected with the other three ; 

 thus the whole four toes are connected together, 

 a circumstance which tends to give great velo- 

 city to the bird when diving in pursuit of prey. 

 There are also some which swim and dive well, 

 but the toes of which are long and slender, and 

 not furnished with webs or fins, as the water 

 hen and rail ; but these, again, live as much on 

 land as water.* 



Most birds, when sleeping, roost on branches, 

 which they grasp firmly with their claws. Here, 

 too, we find a beautiful provision of nature, ef- 

 fecting the constriction, by which they cling to 

 their support, by the manner in which the ten- 

 dons of the flexing muscles of the feet descend 

 along the legs. These tendons press behind the 

 articulation of the heel, while a muscle which 

 arises from the body, joins them as it passes in 

 front of the knee, so that the bird has but to give 

 way to its weight, and the joints becoming salient 

 on the side along which the tendons run, stretch 



* Drummond's Letters. 



