138 SOME IIYOID HINTS. 



peckers there is a spray of fine nerves passing 

 from the hyoid sheath all along its course, 

 and disappearing in the adjoining tissues. 



A minute dissection of the head of Picus 

 villosiis shows that an obscure flat band of 

 fibrous tissue passes over the quadrate bone, 

 from the end of the hyoid sheath, but not 

 from the ends of the cornua. 



Thus it will be seen that Nature has not 

 stultified herself in the discrimination between 

 Picus and Colaptes, in the matter of giving 

 direction to the posterior wanderings of the 

 tongue-attachments, but has answered, in the 

 only safe way, the insistent demand of a 

 great need in each case. Picus must be able 

 to hear his prey, and yet if his ears were 

 sufficiently sensitive, of themselves, for this 

 purpose, the wood-pounding the bird has to 

 do would kill him. So Colaptes must take 

 his food from the ground ; but his bill is not 

 soft and filled w^ith nerves, like the snipe's, 

 therefore he must depend upon his tongue, 

 which in turn is, alas ! a woodpecker's tongue, 

 and cannot be trusted until it has formed a 

 connection with the olfactory cavity ! 



The woodpecker's eyes are immense, in com- 

 parison with the size of the skull, and have a 

 power of vision not surpassed by that of the 

 hawk's or the kingfisher's. Whenever his 

 chosen food can be selected by his eyes, he has 

 no need for any extraordinary disposition of 

 the tongue-bones. 



In treating the case of Colaptes, I have used 

 the idea of gustatory aid derived from the nos- 

 tril, but I doubt if the actual sense of taste 

 is really aided directly, though this is far from 

 impossible. The chief efiiect of the nostril and 

 tongue connection may be the registration (by 

 vibration) of the movements of prey when 

 caught. Thus when the bird, with its beak 

 deep in the ground, draws a worm up into its 



