206 



MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



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"**K^ 



edge of tlie. vaginal process aud sometiines quite within its folds. Below this nodosity there can 



sometimes be seen a second swelling with the same evidences of a suture. Then, again, there are 



many skulls in which the first nodosity is present, and the process is terminated by a truncated 

 extremity, as if a piece had been attached to it, but had been 

 lost in preparation; and, finally, in some few cases the styloid 

 composed of three distinct pieces was observed, as described by 

 Thomas. 



There can be little doubt that the part spoken of by Thomas 

 as the " hyoid prolongation " is the tjonpanohyal element of 

 Flower, Avhich, there is good reason to believe, is variable in 

 length. There is also little doubt that not uncommonly there 

 is a distinct ossification intervening between the lower end of 

 the true styh)hyal element and the ceratohyal piece, or small 

 cornu of the hyoid, which can not be accounted for upon any 

 hypothesis other than that it is the strict homologue of the 

 missing epihyal so constant in the lower forms. It would be a 

 matter of no little interest to determine the frequency of its 

 occurrence in the various races of mankind. (See Figs. 38 

 and 39.) 



Passing now to the hyoid bone proper, we have to consider 

 the several elements of which it is composed. As is well known, 

 it is generally described in works on human anatomy as con- 

 sisting of a single u-shaped bone, formed by the union ^f five 



pieces. These are known as the body and the greater and lesser cornua. Although there does 



not appear to be absolute unanimity of opinion among anatomical writers regarding the particular 



time of life when these elements coossify, we can not do better than to 



(piote here the statements made by the leading anatomical authorities 



upon this point. 



Among the German anatomists Meckel, in his Manual of Anatomy, 



says : 



" The hyoid bones, or the hyoid bone, forms an arch which is convex forwards. 



It is situated behind and below he maxillary, beneath the root of the tongvie aud 



the upper part of the neck. It is generally considered a single bone, aud is divided 



into a central portion, or body and four horns, two upon each side; but as these 



parts remain distinct throughout life it is better to admit five distinct bones, a 



middle and four lateral. The inferior hyoid bones, or the greater cornua of the 



hyoid, often vary considerably in form and size upon the different sides in the same 



subject. They articulate with the central piece by a iibro-cartilaginous mass and 



sometimes unite in the latter periods of life in one bono." 

 Heule, in his Human Anatomy, says : 

 ' ' The great horns of the hyoid bone can also be connected with the body by joint. Many hold this to be the rule." 

 Hyrtle, in his Lehrbuoh der Anatomie des Menschen, says, quoting from Meckel : 

 " The 08 hyoid is divided into central or body aiultwo lateral cornua, which p.irta, as they are united by uiovable 



[After 



vv 



.—Styloid process of man. 

 [After Thomas] 



articulation or by synchondrosis, and often in old 

 rate hyoids." 



Gegenbaur, in his Lehrbuch der Anatomie des Menschen, says : 



"The great cornua often coossify with the body." 



Hartmann, in his Handbuch der Anatomie des Menschen, says: 



"The live parts of the hyoid bone articulate by movable joiut at the small horns .and 

 large horns. In old ago these parts are ofttimes anchylosed." 



Krause, in his Menschliche Anatomie , says : 



" The great horns are united with the body by capsular ligament, aud the joiut is an ai 

 it is only a synchondrosis." 



tied, can be cousidered as so many different or sepa- 



itli synchondrosis at i 



iphiarthrosis. Very often 



