130 SOME UYOID HINTS. 



lar, membranous, and nervous tissues, and it 

 divides into two horns, which passing back- 

 ward and upward, reach forward over the top 

 of the skull, and down to the base of the 

 upper mandible, or into the nostril, or curl 

 under the right eye and rest almost, or quite, 

 against the front of the quadrate bone. In 

 making this circuitous passage the forks of 

 the tongue-bone go on either side of the neck 

 and come together, without coalescing, on the 

 back of the skull, whence they remain touch- 

 ing each other and parallel, to the end of their 

 course. 



In the genus Picus, of wliich I take the 

 hairy woodpecker as the typical species, the 

 hyoid cornua (forks of the tongue-bone) end 

 their peculiar journey below and rather pos- 

 terior to the bird's right eye. 



In the genus Melanerpes, of which our 

 white-and-black red-head is typical, the ter- 

 minus is on the central front of the skull, just 

 above the base of the upper mandible, whilst 

 the genus Colaptes, to which our flicker be- 

 longs, has its hyoid cornua prolonged into 

 its nasal cavity by way of a nostril. 



In each case, throughout its entire course, 

 this peculiar hyoidean process is sheathed in 

 a curiously-woven wisp of muscles and 

 nerves, which is modified and prolonged be- 

 yond the bony parts, most peculiarly in the 

 instances of Picus and Colaptes. * 



The most obvious function of this strangely 

 specialized hyoid process is to give a great 

 thrust to the tongue, so that it may be pro- 

 jected far beyond the end of the bill. The 

 longer the hyoid cornua the farther the tongue 

 can be thrust out of the mouth. So that it 

 has been taken for granted, so far as I know, 

 that the curling of the cornua over the sku!l 

 between the skin and the bone, was merely 

 the most handy and economical way of dis* 



