PERRAULT AND HIS COLLEAGUES 233 



[in the purely insectivorous woodpeckers] is armed with 

 minute, backward-pointing teeth [M^ry says six on 

 each side, but the number may be much greater than 

 six]. To render the tip of the tongue yet more effective 

 in picking up insects, it is covered with a viscid fluid, 

 the secretion of large salivary glands. The hyoid bone, 

 which, as usual, supports the tongue, is straight, slender, 

 and about two inches long.^ It gives off behind a pair 

 of very slender branches (cornua), which are no less than 

 six and a half inches long. When the tongue is at rest, 

 the cornua curve round the sides of the neck, pass over 

 the top of the head, and then, bending to one side, end 

 together in the right nostril [sometimes in the left one]. 

 The top of the skull is excavated by a groove, in which 

 the cornua lie, and the hyoid, with the bases of its 

 cornua, are enclosed in a sheath, whose cavity opens into 

 the mouth.^ M^ry goes on to describe the muscles of 

 the tongue. There is a pair of protrusors, which connect 

 the cornua with the lower jaw ; when they contract, the 

 cornua and tongue are drawn forwards and protrude 

 from the mouth. Two elastic ligaments attach the tips 

 of the cornua to the nostril ; these become stretched 

 during protrusion, and during retraction help to return 

 the cornua to their position of rest. A pair of retractor 

 muscles make the windpipe their fixed point, and are 

 inserted into the sheath. Other muscles raise, depress, 

 or bend the tongue to one side. The long protrusors are 

 wound about the cornua, and the long retractors about 

 the windpipe — curious examples of economy of space. 

 By these arrangements the requisite length in both 

 cornua and muscles is obtained, while the parts are so 



1 The dimensions given relate to Mery's " piver," our green woodpecker. 



2 In humming-birds, which like the woodpeckers have a protrusible tongue, 

 both the furrow on the skull and the sheath are double. 



