306 ON THE CLASSIFICATION OF BIRDS. 
moved from the culmen. Versatile toe always lo 
_ than the anterior.* (fig. 275.) _ 
Picus, Sw. Lateral ridge situated nearer to the edge 
than to the culmen. Bill with the sides compressed. | 
Neck long, and thin. Versatile toe considerably 
lengthened. America and India. 
P. robustus. Spix, pl. 44. principalis. Wilson, 29. f. 1. 
Hemicircus, Sw. Tail excessively short, and very broad. — 
Neck short, very slender. Bill straight, considerably 
compressed. Lateral ridge slight, near to the margin. © 
Nostrils concealed. Feet very large. Versatile toe 
always longer than the anterior. Wings nearly as” 
long as the tail. India. 
H. concretus. Pl. Col. 90 , | 
Dendrobates, Sw. Lateral ridge close to the margin. 
Sides of the bill much compressed ; the base wide. 
‘ Versatile toe usually longer than the anterior. Plum-— 
age, olive above, generally spotted or banded. Africa 
only *, excepting two species from Tropical America. 
D. fulviscapus. Ois. d’ Af. pl. 253. 
Apternus, Sw. Lateral 
ridges close to the 1) 
margin. Bill rather . WT CV fy 
broader than high. iy j & 
Feet three-toed ; the 
two. anterior nearly 
equal, the posterior 
much longer. Arctic 
regions. (fig. 276.) 
A. Americanus. N. Zool. pl. 56.4 arcticus. N. Z. pl. 57a) i 
ry 
* I use these terms for the sake of brevity : the versatile toe is the oute 
posterior toe, and the anterior is the outer fore toe, corresponding to the — 
middle one of ordinary peckers. 
¢ It being now ascertained that this is a distinct species from the Euro- 
pean ¢ridactylus, another name is necessary to designate it. 
