26 INTRODUCTION. 



bare, Fig. 6, or covered with feathers, Fig. 7, as may even 

 the toes, Figs. 8 and 3. 



Fig. 6. 



Although in quadrupeds the number of toes or fingers is 

 very frequently five, no birds have so many. By far the 

 greater number have four, but very many have only three, 

 and one species, the Ostrich, has no more than two. The 

 hind toe is the first, the inner toe the second, the next the 

 third, and the outer toe the fourth. The fourth toe is always 

 present, so is the third, the second and first are wanting in 

 the Ostrich ; and it is the first or hind toe that is wanting in 

 all birds that have only three toes. In the first toe there are 

 always two joints, in the second three, in the third four, and 



