162 ELEMENTS OF ORNITHOLOGY, 
by small feathers for its whole length, as in the Barn Owl, some 
Eagles, and the Grouse, or it may be only partly feathered. 
The toes are normally feathered also in some Owls and in the 
Ptarmigan. 
Abnormally, feathers grow on the feet which resemble the 
long feathers of the wing. Such feathers may be found on the 
feet of Trumpeter Pigeons and Bantam Fowls, and structures 
of this kind are called “boots.” These extra feathers are 
attached to the outer side of the foot, just as the primaries of 
the wing are to the outer side of the pinion. ‘These foot- 
feathers have been known to exceed the wing-feathers in length, 
which they resemble not only in size but in structure. 
The skin of the bare portion of the limb is almost always horny, 
but may be somewhat leathery, as, e g., in the Duck and most 
aquatic birds. The epidermal covering is more or less divided 
into scale-like segments. If these are very small they are said 
to be reticulate; if they form largish quadrate segments the 
part so invested is scutellate; but the tarsus may be invested by 
a continuous horny plate in " front—or along what is called the 
acrotarsium—when it is said to be booted or greaved. When 
the reticulations are in the form of little prominences which 
roughen the legs, such a covering is granular; and if a scutel- 
late part is so formed as to make the leg rough, it is called 
scarious, Its prominences may be so sharp as to be termed 
serrations. The wrinkled surface of the web of palmated feet 
is spoken of as cancellated. 
Different naked parts of the limb may be differently invested. 
The whole naked epidermal investment. is named the podo- 
theca. If this is divided into many subdivisions, itis said to be 
schizothecal, The lateral and the hinder surface of the tarsus, or 
the planta, may be invested with scales or scutellate—a condition 
termed scutelliplantar—or it may be covered with reticulations. 
But each lateral surface may be clothed with only one continu- 
ous plate, which meets its fellow at the middle of the back of 
the tarsus, the junction of the two forming a prominent ridge ; 
such a condition is denominated laminiplantar, and the co- 
existence of this condition with a continuous horny plate in 
front of the tarsus forms a podotheca, the very opposite to that 
termed ‘ schizothecal.” By contrast, therefore, it is distin- 
guished as holothecal—a “ holothecal podotheca.” A tarsus may, 
however, be laminiplantar and yet scutellate in front, or it may 
be scutellate in front and reticulate laterally and behind, or it 
