DEVELOPMENT OF THE ENAMEL 185 



While there is no evidence of the presence of blood- 

 vessels in the enamel organ of the Gadidae, in Sargus they 

 form a very important and regular portion of its structure. 

 In specimens where a portion of the enamel has escaped 

 decalcification it is seen that both systems of tubes stop 

 short of the forming enamel, a narrow interval separating 

 them from it. This interval is occupied by a delicate 

 reticulum filled with fine granules and larger scattered bodies 

 which appear to be calcospherites deposited in this reticular 

 structure. The tubular structure of the finished enamel of 



FIG. 103. A portion of the enamel organ of Sargus ovis, showing the 

 relations of the tubular organ with the vascular tubes and the cells with 

 their nuclei which occupy the spaces between them. Abbe prism drawing. 

 ( x 290.) c. Capsule with blood-vessels ; t. secreting tubes and cell nuclei ; 

 b. blood-vessel tubes. 



Sargus is not due to the actual passage of these tubular 

 structures into the forming enamel (at all events until 

 calcification reaches the inner circumference of the capsule), 

 for they do not reach it, and the pattern of the enamel is 

 laid down by the delicate organic stroma in which calcifica- 

 tion takes place, the vascular and secreting tubes and cells 

 taking the part in this calcifying process which is fulfilled 

 by the ameloblasts in Mammalia. 



Tomes, in his paper, speaks of the apparent anomaly 

 in the Gadidse that the lime salts are separated from the 

 blood at a distance from the place where they are deposited. 

 This certainly does not appear to be the case in the Sparidae, 

 for the materials for calcification can be elaborated within 

 the enamel organ itself, the blood-vessels and secreting cells 



