THE ATTACHMENT OF TEETH 361 



posterior hinge (Plate VI A). Serial sections show that when 

 the central longitudinal axis is approached, this band is no 

 longer visible, and the thickened portion of the lower end of 

 the dentine lies free in the section, portions of the pulp only 

 being attached to it. 



This apparatus is perfectly adapted to the capture of 

 active prey ; the small fish and other creatures which form 

 the food of the Hake depress the teeth on entering the 

 mouth, a very slight pressure only being necessary, and their 

 escape is prevented by the springing back of the teeth into 

 position. 



The passage of the captured creature backwards in the 

 mouth is still further facilitated by the hinged teeth on the 

 vomer and pharyngeal bones. 



Most of these predatory fish swallow their prey in a whole 

 and living condition, and their teeth are not available for 

 any process of mastication. 



In other members of the Cod family a transitional form 

 of hinging is met with. In the Haddock (Gadus ceglefinus) Haddock, 

 the tooth rests upon a ring of what appears to be dentine, 

 which becomes blended below with the bone of attachment. 

 The upper part of the tooth is quite separated from this 

 lower portion so far as the continuity of the hard tissues is 

 concerned, but surrounded at the point of contact with a 

 fibrous band forming a kind of capsular ligament which is 

 attached to the circumference of the portions above and below 

 the flange. This evidently forms a hinge and allows (fig. 240) 

 of a limited amount of rocking movement, as can be seen in 

 several sections where teeth are seen to be inclined to one side, 

 the opposite side of the ligament being stretched. The pulp, 

 as pointed out by C. S. Tomes, is continued into the cavity 

 below the flange, and he describes odontoblasts in this 

 portion of the pulp, so that we must look upon the tissue 

 in this part of the tooth as a not very clearly defined dentine, 

 and as this author states, its implantation would indicate 

 a transition in the teeth of the Haddock to a socketed type. 



The hinged teeth of the Angler (Lophius piscatorius) are Angler. 

 attached by radiating fibrous ligamentous bands to the bone, 

 the front of the tooth being free and resting on the bone, 

 but there is no definite differentiated elastic hinge as in the 



