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A MANUAL OF DENTAL ANATOMY. 



When the teeth are, as in many fish, implanted upon 

 what to the naked eye appears nothing more than a plane 

 surface of bone, a microscopic examination generally, in fact 

 in all specimens which I have examined, reveals that the 

 individual teeth are implanted in depressions much larger 

 than themselves, the excess of space being occupied by new 

 and specially formed bone, or else that the teeth surmount 

 pedicles, which are closely set together, the interspaces being 

 occupied with a less regular calcified structure. 



A good example of the latter method is afforded by the Eel 



Fro. 90 ('). 



(Fig. 90), in which each tooth surmounts a short hollow cylin- 

 der of bone, the lamination, &c., of which differs strongly 

 from that of the body of the jaw-bone. When the tooth which 

 it carries is shed, the bone of attachment, in this case a hollow 

 cylinder, is removed right down to the level of the main 

 bone of the jaw, as is well seen in the figure to the left of 

 the teeth in position. Under a higher magnifying power 



('*) From lower jaw of ail Eel. a. Bone of jaw. 6. Bone of attach- 

 ment, d. Dentine. /. Enamel, g. Space vacated by a shed tooth. 



