478 
SYSTEM A TIG SYNOPSIS. — PICAEI^ — PICIFOBMES. 
lengtli of the outer hind toe, are characters which diminish or are lost together as we pass from 
the Ivory-bill extreme to the Flicker end of the series. The claws are always large, strong, 
sharp, and much curved ; the feet do not present striking generic modifications, except in the 
three -toed genus Picdides; the length of the outer hind toe is the most variable factor. The 
wings are specially noteworthy, for the shortness of the coverts, in exception to the Picarian 
Fig. 329. — Ivory-billed Woodpecker, \ nat, size. (From Brehra. ) 
rule; and the shortness of the first primary, which may fairly be called spurious; but these 
points and the remarkable character of the tail have been already mentioned. This member 
offers indispensable assistance in climbing, when the stiff strong quills are pressed against the 
tree, and form a secure support. To this end, the muscles are highly developed, and the last 
bone {vomer or pygostyle) is large and peculiar in shape. Woodpeckers rarely if ever climb 
head downward, like Nuthatches, nor are the tarsi applied to their support. 
