118 OS HTOIDES. 



of permanent teeth have consisted of double or molar teeth all 

 round. Sometimes the appearance of the temporary teeth has 

 been protracted to the sixth or seventh year, and even then 

 followed at regular intervals by the permanent set. The 

 number of the permanent teeth are sometimes less than usual, 

 in consequence of the non-development of the wisdom teeth, 

 which remain locked up in the jaw, and occasionally produce 

 pain, and even abscesses in the bony structure. 

 — Sometimes there are supernumerary teeth. Haller has seen 

 in an infant of fourteen years, seventy-two teeth, thirty-six in 

 each jaw, which appeared to depend upon a greater number 

 than usual of the dental germs. Some, fond of the marvelous, 

 have described the eruption of a third set of teeth analogous to 

 the two first : but according to Hudson and others, this 

 appearance has probably been owing to the tardy removal of 

 the deciduous set, and the late supplial of their place by the 

 permanent teeth. 



— Sometimes the direction of the teeth is vicious, leading into 

 the ramus of the jaw, or upon the outer or inner surface of the 

 gums ; or upon the roof of the mouth. Accidental develop- 

 ments of teeth have likewise been met with in the orbit, the 

 tongue, pharynx, stomach, and not unfrequently in the ovaries 

 and uterus. — 



Os Hyoldes. 



The OS hyoides is a small insulated bone, supported between 

 the lower jaw and the larynx, by muscles and ligaments, 

 which proceed from the neighboring parts in various 

 directions. 



The figure of this bone, as its name imports, resembles the 

 Greek letter v. In its natural situation, the central and convex 

 part is anterior, and the lateral portions extend backwards. 



The central part is called the hody, and the lateral portions 

 the cornua. 



The body is broad and its upper edge bent inwards, so that 

 the external surface is convex, vertically, as well as horizon- 

 tally. On this surface is a horizontal ridge : the muscles 

 which proceed from the lower jaw are generally inserted 



