OSTEOLOGY OF BIRDS 221 



ganization in them of the corresponding parts. -It has been said, 

 as we know, that they have double vomers in adult life — but this 

 was disputed by Garrod [Ibis, 1872, p. 357-60], who claimed to 

 have found a median vomer for the woodpecker, and in which 

 the present writer believes him to have been correct.^ 



A careful comparison of the mandibles of these two series of 

 turkey skulls, fails to reveal to me any constant set of characters 

 that can in any way be relied upon to distinguish those belonging 

 to the wild ones from those of the domesticated variety. 



I have also compared the hyoid arches, the sclerotal plates of 

 the eyeballs, and other minor ossifications about the skull, and what 

 I have just said in regard to the mandibles, applies with equal truth 

 to them ; there are no reliable characters to distinguish them. 



This brings my comparisons of these two series of skulls to a 

 close, and I will here complete what I have had to say by a brief 

 recapitulation of the constant characters which, so far as I have 

 been able to ascertain, seem to distinguish the skull of a wild turkey 

 from that of a domesticated one, the latter being descended from 

 domesticated stock of long standing, and as free as possible from 

 any mixture with the wild types. 



In drawing up this summary, I would have it distinctly under- 

 stood that only the most constant differences have been selected, 

 and exceptions even to these may occasionally be found among tame 

 turkeys, where for some unknown cause, they seem, in certain 

 individual cases, to revert again to the cranial structure of the wild 

 species. 



These selected characters will, however, show the tendency to 

 the changes that are taking place and are apparently, up to the 

 present time, typified in the skull of the tame turkey which I have 

 chosen in the figures to illustrate them. I take it that these changes 

 are still in somewhat of a transitional stage, and that eventually 

 tame turkeys will differ very v/idely from the wild ones, and that 

 this difference will become much greater and more rapidly brought 

 about when the breeding and selection of turkeys is more carefully 

 looked into, with the view of introducing certain improvements in 

 them. 



' In this place I desire to say that the figures of skulls of turkeys drawn by me, 

 and illustrating the present treatise, have passed into textbooks without a word of 

 acknowledgment as to authorship. The most glaring piracy of this character has been 

 committed by M. Edmond Perrier of Paris, who used the entire set in one of -his 

 woiks upon comparative anatomy as though he had made the original dissections. 



R. w. s. 



