Key to the Species. 
A. The culminicorn golden-yellow ; sides 
black ; culminicorn not reaching to 
frontal feathers (see fig. 1) 
Th. chlororhynchos bassi, p. 281 
Th. chlororhynchos carteri, p. 287 
B. Bill all black ; same shape 
C. The culminicorn yellow, reaching to the 
frontal feathers ; the lower edges of 
lower mandible pale (see fig. 2) . . Th. chrysostoma culminatus, p. 277 
D. The culminicorn pale grey unicolor ; not 
reaching to the frontal feathers (see 
fig. 3) . . . . . . . . Th. cautus cautus, p. 289 
Note. — T he figures given are by far the best key to the species. 
276 
