125 
EXTERNAL ANATOMY. — ’ FEET. 
should have conjectured from this singular and, m 
many respects, unique construction of foot. The colys 
walk but badly ; but, when at rest, unlike all other birds, 
they hang from the branches with their heads down- 
wards ! — precisely similar to bats ! Lastly, we may 
number the corvorants, whose four toes are all directed 
forwards, and all of unequal lengths, gradually dimi- 
nishing from the outermost; a broad web connecting 
the whole. Of the use this particular structure is to 
these birds we can form no idea. It is known, indeed, 
diat they are most expert divers and good swimmers ; 
and that, when upon land, they stand almost erect, sup- 
ported by their rigid scansorial tail. 
(114.) We are now to consider those Four-toed feet, 
which are constructed upon the common principle of thr^ 
anterior and one posterior. This ilisposition is seen in 
the great majority of birds, and consequently it admits of 
much greater variety in its secondary modifications than 
those structures we have just been describing. It is 
impossible to assign to any one of the forms of foot, 
possessing this disposition of the toes, a decided supe- 
riority of perfection in aU functions, any more than can 
be done in the (|ualities or functions of the birds them- 
selves. A raptorial and a perching foot are equally 
perfect ; yet their perfections are of different kinds. A 
union of many qualities, without having any one more 
eepevially developed, is always found to indicate typical 
pre-eminence ; and upon this principle the most perfect 
feet are possessed by the perching birds of the order 
Ineessorex. Then as to size. The smallest feet are 
found in the Natatorial or swimming order, while the 
largest belong to the Rasorial. This may be considered 
a law of nature, not only among birds, but throughout 
the class of quadrupeds ; and it is as apparent in the 
animals really belonging to these two types as in those 
groups which analogically represent them in other cir- 
cles. It must be remembered that it is only the hindet 
feet of quadrupeds which can be justly compared with 
those of birds, liecause the fore feet of the former be- 
