COMPARING FEET. 



95 



close cousins of the sandpipers, have the webbing extended 

 along both sides of their toes, in a scalloped edge. 



Again we find another variation for increasing the surface 

 in the excised web, in which the space between the toes is still 



FIG. 22. EXCISED WEB FOOT OF 

 BLACK TERN (LIFE SIZE). 



FIG. 23. PALMATE OR WEBBED Fooi 

 orDucK (REDUCED). 



more filled up, though the word signifies that the foot looks as 

 if it had once been full-webbed and then cut out, or excised. 

 In the ducks and geese we see the webbing carried out to the 

 toe-nails, and the surface increased by spreading the toes wide 

 apart. In the loons it is still further increased by lengthening 

 the toes, which make the 

 webs long as well as wide. 

 But one other device seems 

 possible, and that we find in 

 the totipalmate birds, where 



FIG. 24. TOTIPALMATE FOOT OF 

 GANNET (GREATLY REDUCED). 



all four toes are joined by 



the web. Observe, please, 



that in these the outer toe is 



longest while in all other web- footed birds the third, or middle, 



toe exceeds the others. 



Most palmate birds swim with alternate strokes, now right, 

 now left, or with one foot a little behind the other, seldom 

 with both exactly together. The swans often swim with only 



