ENAMEL 



89 



fuchsin staining method were from a dry preparation of the 

 upper and lower jaws of a Mediterranean species of Sargus, 

 S. noct. In this fish, unlike S. ovis, there is a very free 

 penetration of tubes from the dentine as well as from without. 

 In fig. 43 it is seen that the dentinal tubes enter the enamel 

 in radiating bundles and pass right across it, interlacing with 

 the tubes from the outside. At the dentine margin they 

 spread out a little from the close bundles and bend slightly 

 towards one another before spreading out into the enamel. 



FIG. 43. Sargus noct. Completed enamel. 

 d. Dentine; e. enamel. ( x 50.) 



These dentinal tubes are very abundant and deeply stained ; 

 many can be followed to their terminations close to the free 

 margin, while others are lost in small oblong bundles of tubes 

 formed by those of the outer tube system. These two 

 separate systems of tubes crossing one another in many direc- 

 tions form, with the twisted and spirally arranged prisms, 

 a more intricate and complicated pattern even than in 

 Sargus ovis. Many of the tubes from the dentine divide 

 and branch, as do also those from the outside, but the 

 majority of the tubes of both systems pass in more or less 

 even curves across the enamel, interlacing with one another. 

 This penetration by both sets of tubes does not appear to 



