THE ATTACHMENT OF TEETH. 211 



the bone at this point would be found to be excavated by 

 "Howship's lacunae." As an anchylosis, the implantation 

 of the teeth is less perfect than that of those of the snake, 

 for the dentinal tubes at the base of the tooth are not de- 



FlG. 91 



fleeted, and do not in any sense blend with the bone beneath 

 them. Accordingly, the teeth are far less firmly attached, 

 and break off quite readily. 



A transition towards the socketed type of implantation is 

 furnished by some of the cod tribe. In the haddock, for 

 example, the teeth surmount hollow cylinders of " bone of 

 attachment," resembling in many particulars those of the 

 eel ; the teeth do not, however, simply surmount the boiiv 

 cylinders, but are continued for a short distance within 

 them, definite shoulders being formed which rest on the 

 rims of the cylinder. The base of the tooth does not, how- 

 ever, contract or taper any more, and is widely open, so that 

 it cannot be considered that any close approximation to a 

 root is made. The pulp cavity of the tooth becomes con- 



(*) From lower jaw of a Haddock, a. Bone of jaw. 1>. Bone of attach- 

 ment. </. Dentine of tooth. 



p -J 



