THE GOLDEN-WINGED WOODPECKER. 



289 



consequently have the power of thrusting out their tongue to a much greater 

 extent than others. Thus: 



In Picus varius, the tips of the horns of the hyoid bone reach only to 

 the upper edge of the cerebellum, or the middle of the occipital region. 



In Picus pub escens, they do not proceed farther forward than opposite to 

 the centre of the eye. 



In Picus 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 curve round the right orbit to opposite the 

 middle of the eye beneath. 



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

 ment, 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. 



Vol. IV. 



40 



