212 A MANUAL OF DENTAL ANATOMY. 



tinuous with the cavity of the osseous cylinder, into which 

 it is for a short distance continued. 



The bony supports of the teeth originate in many osseous 

 trabeculse which spring up simultaneously from the bone of 

 the jaw beneath the new tooth ; these coalesce to form a 

 net-like skeleton, which rapidly becomes filled in by the 

 progress of ossification. So far as my own researches enable 

 me to say, there is this much in common in all forms of 

 attachment by anchylosis, no matter how different the 

 naked eye results of the process may be ; the tooth, as it 

 comes into position, is secured by an exceedingly rapid 

 development of bone, which is more or less directly an 

 outgrowth from the jaw-bone itself, which is in some un- 

 seen manner stimulated into activity by the proximity of the 

 tooth. In amount this specially formed bone varies greatly, 

 but in all instances it is not the tooth capsule, but tissues- 

 altogether external to this, which serve to secure the tooth 

 in its place by their ossification. 



The teeth of the mackerel present an interesting variety of 

 attachment by anchylosis. The margins of the jaws are very 

 thin, and by no means fleshy, and in this thin margin there 

 is a deep groove between the outer and inner plate of the 

 bone. In this groove are the teeth, their sharp points pro- 

 jecting beyond the edges of the bone, and they are held in 

 their place by a network or scaffolding of bone of attach- 

 ment which is developed between their sides and the inner 

 surface of the bone. They are, so to speak, hung up in their 

 place, and their open bases rest on nothing, or at least on 

 nothing hard. 



Attachment by implantation in a socket. In this, 

 as in anchylosis, there is a special development of bone, 

 which is modelled to the base of the tooth, but instead of 

 its being in actual close continuity with the dental tissues, 

 there intervenes a vascular organised membrane. The 

 manner in which the sockets are, so to speak, plastered 



