LEGS 29 



Length of leg. — The proportional length of leg and body of 

 birds is extremely variable. The leg is very short in swallows 

 and in all true swimming birds, medium in sparrows, longer in 

 hawks, very long in the ostrich, and exceedingly long in 

 cranes, stilts, and wading birds generally. The tarsus varies 

 from about one thirtieth to one third the full length of the bird. 



Number and arrangement of toes. — The usual number of toes 

 is four, and among the birds of our region there are but few 

 exceptions. The only other number represented in our fauna 

 is three ; but the ostrich lias only two. When the toes are four 

 in number they are arranged in three ways. The most com- 

 mon of all is shown in the sparrow, in which there are three 

 toes in front and one behind} In order to understand the modi- 

 fications of this common plan, it is well to give names and 

 numbers to the toes. The hind toe represents the great or 

 inner toe of the human foot, and is called the hallux or first toe ; 

 the inner front toe is the second toe ; the middle one the third 

 toe; and the outer the fourth toe (see cut, p. 16). These, 

 •with few exceptions, have the following number of joints : 

 the first toe two-jointed, the second three-jointed, the third 

 four-jointed, and the fourth five-jointed. Some of our birds 

 have the first toe absent, as will be shown hereafter ; all the 

 rest have joints as given, except the goatsuckers, which have 

 but four joints to the fourth toe. 



The second plan for the arrangement of four toes is shown 

 in the woodpeckers, parrots, etc. In these there are two in 

 front and two behind.'' The first and fourth toes are behind, 

 and the second and third in front. 



The third plan is represented in the owls. In these, the 

 first toe is permanently behind, the second and third perma- 

 nently in front, and the fourth can be used either in front or 

 behind,* and for this reason is called a versatile toe. 



4st 



