i^09^ VI ] Townsend, Use of Wings and Feet by Diving Birds. 243 



tanks use the feet and not the wings under water, and Selous (18) 

 believes that the Coot belongs "to the cormorant-school of diving." 

 This he infers from the manner of its entering the water. He 

 apparently has not seen it under water. 



I have no observations of my own to record on Rails proper and 

 Gallinules but Selous (21) says of the English Moorhen, Gallinula 

 chloropus, that he "may follow no fixed plan in his diving, for I 

 have certainly seen him using his feet only under water, and I 

 believe I have also seen him using his wings." Lea (12) says of 

 the Moorhen: "After diving, it flies through the water at a great 

 pace." 



Among the Shore-birds the young of the Spotted Sandpiper are 

 said to use both wings and feet in diving. 



The impetus of the Kingfisher is probably all that is needed by 

 this bird in its plunge, but it is possible that it occasionally scrambles 

 a bit with its wings under water, — its feet can hardly be of use. 



Among Passerine birds the water Ousel is the only diver, and it 

 is well known that this bird uses its wings under water, and many 

 observers state that it uses also its feet (13). 



From the result of these studies it seems reasonable to conclude 

 that diving birds tend to specialize in two directions, — either 

 towards the use of the feet alone, or of the wings alone. The ques- 

 tion naturally arises as to which line is superior, which has pro- 

 duced the swiftest diving bird,— the line that has lead to the use of 

 the feet alone or that which has lead to the use of the wings alone ? 

 It is evident that a method of diving which leaves the wings unim- 

 paired in size or form for the use in the air is a desirable one, and 

 this is possible where the feet alone are used. In most fishes pro- 

 pulsion is from the rear by means of the tail, for the pectoral fins, 

 which correspond to the birds' wings, are used chiefly for balanc- 

 ing. When the fish swims fast these fins are kept close to the 

 sides. Among mammals the cetaceans have developed greatest 

 speed in diving and swimming under water, and here also the tail 

 is the propulsive power, while the anterior extremities are used 

 chiefly for balancing. The modern screw propeller is superior to 

 the old side-wheeler. 



In Hesperornis the wing is a mere vestige, reduced to a slender 

 humerus only, without even articulating facets on the distal end. 



