310 
ON THE CLASSIFICATION OF BIROS. 
but with a faint lateral ridge close to the basal half 
of the culmen. Tip of the upper mandible wide and 
depressed. Wings very short. Tarsus, anterior and 
versatile toes, all of the same length. Africa only. 
G. terrestris. BurchclI. Ois. d’Af. pi. 264. 
Colaptes. Bill considerably compressed. Culmen arched 
from tile base. Lateral ridge entirely wanting. Tarsus 
longer than the versatile toe. \Tingslong. (Jig.ZT'i.b,e) 
C. auratus. Wils. pi. 3. f. 1. Mexicanus. N. Zool. ii. 315. 
Mf.lanerpes, Sw. Bill straight, more or less cylindri- 
cal : base wide : the ridge of the culmen slightly bent, 
but not very prominent : the sides rounded ; the la- 
teral ridge slight, and placed near, but not close to, 
the culmen. Gonys very long, as in the typical 
group. Nostrils nearly concealed. Wings long; the 
first quill spurious, or very small ; the second nearly 
as long as the third. Toes various. Habits gregari- 
ous and migratory. Colours black, varied with white 
and red. The fissirostral type. America only. 
Centnrus, Sw. Gonys angulated, half as long as the 
under mandible. Lateral ridge alxiut half the length 
of the culmen, which is gently curved. Sides of the 
bill compressed... Tarsus .shorter than the versatile 
toe ; the anterior rather longer. Plumage, above, black 
banded with white, 277- c) 
C. Carolinensis. Wils. 7 . f. 2. bracliypterus. Sw. sp. nov. 
Tjeueomrpes, Sw. Bill as in Melanerpes, The base 
wide, but the sides much compressed. Lateral ridge 
placed half way between the culmen and the margin. 
AVings long. Versatile toe shorter than the anterior. 
Tarsus shorter than either. 
L. candidu.'!. Zool. III. i. pi. .38. 
MelanerpeJi, Sw. Bill straight, the base wide ; the 
sides not compressed. Gonys long, and equally curv- 
ing to the tip with the culmen. Versatile and ante- 
rior toes equal. Tarsus much shorter. AVings long, 
reaching almost to the end of the tail. 
IVI. erythrocephalus. Avails. 9, f. 1. torquatus. Ib, 20. f. 3. 
