188 MICROSCOPIC ANATOMY OF THE TEETH 



vessels to the calcifying stroma. At this stage there is 

 no vestige of an ameloblast layer or of an external epithelium, 

 the outer margins of these bodies being only separated 

 from the connective tissue of the capsule by a delicate 

 basement membrane. In the earliest germs of Tautoga, 

 as in Sargus and the Gadidse, an ameloblast layer and an 

 external epithelium are present, but very soon a remarkable 

 change takes place in the enamel organ. 



At the time when a narrow layer of enamel is laid down 



FIG. 105. The vascular tubes in Tautoga teased out. ( x 500. \ 



and no dentine is formed, and no differentiation of any 

 odontoblast layer in the pulp, a mass of epithelial tissue is 

 seen to have penetrated the capsule from without and to 

 be enveloping the enamel organ very much as the first 

 epithelial inflection envelops the dentine papilla in mamma- 

 lian tooth germs. The external epithelium together with 

 the ameloblast layer soon disappears, and the whole of 

 the circumference of the enamel organ is occupied by 

 this gland-like tissue and the penetrating blood-vessels. 



At this stage, then, we have an enamel organ made up 

 of blood-vessels or vascular tubes, gland-like tissue, and 

 a granular stroma intervening between this tissue and the 



