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 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 /oitr, and 
