WOODPECKERS. 



543 



In Picus pubescens, they do not proceed farther forward than op- 

 posite to the centre of the eye. 



In Ficus principalis, they reach to a little before the anterior edge 

 of the orbit, or the distance of |- inch from the right nostril. 



In Picus pileatus, they extend to half-way between the anterior edge 

 of the orbit and the nostril. 



In Picus erythrocephalus, they reach to 3 twelfths of an inch from 

 the base of the bill. 



In Picus tridactylus, they reach the base of the ridge of the upper 

 mandible. 



In Picus auratus, they attain the base of the right nasal membrane. 



In Picus canadensis, they cm-ve round the right orbit to opposite 

 the middle of the eye beneath. 



Lastly, in Picus villosus, they receive the maximum of their de- 

 velopment, and, as represented in the accompanying figures, curve round 

 the right orbit, so as to reach the level of the posterior angle of the 

 eye. Fig. 1 is a lateral view of the parts, shewing the hyoid bones 

 curving round the eye. Fig. 2 shews these bones as viewed from above. 



