THE PRINCIPAL BIRD GROUPS 97 



be again separated into half-a-dozen sub-fami- 

 lies, which we will shortly specify. Taking the 

 Plantain-Eaters first, we find that they differ 

 from the Cuckoos in several important respects, 

 although obviously very closely allied to them. 

 The feet in this sub-order are only semi-zygo- 

 dactylous, the outer toe being reversible. The 

 bill is stout, the culmen being rounded or 

 compressed and serrated or denticulated along 

 the margin. In two species the base of the 

 bill is modified into a frontal shield. The 

 contour feathers are furnished with an after- 

 shaft ; the wings and tail are rounded, the latter 

 composed of ten rectrices. All the species but 

 one possess erectile fan-like crests. Plantain- 

 Eaters either live in companies or in scattered 

 pairs. They are arboreal species, shy and 

 restless, and feed on fruits, insects, worms and, 

 it is said, small birds. Their notes are loud 

 and discordant. Their flight is somewhat un- 

 even, yet on occasion well sustained. So far as 

 is known, the Plantain-Eaters construct rough 

 platform-like nests in the branches, and their 

 eggs are pale blue. The young are hatched 

 naked. A very remarkable peculiarity should 

 be mentioned respecting the plumage of these 

 birds. The crimson feathers yield a peculiar 



