FISHERY BULLETIN: VOL. 82, NO. 1 



B 



FIGURE 10.— Tooth cementum of dolphin carcass WFP 669. A. TCL labels interpreted as corresponding to 

 lettered dentinal labels (150X). B. Positions of TCL labels (arrows) in layered cement. About 10 GLGs are 

 indicated (150X). 



resented the same amount of time as a dentinal GLG, 

 i.e., 1 yr (e.g., Fig. 10B). In other cases, where labels 

 were absent or where only one label occurred, cali- 

 bration of cemental GLGs with dentinal GLGs was 

 made indirectly by comparing GLG counts from both 

 tissues. This method usually demonstrated a one-to- 

 one relationship of GLGs in dentine and cementum, 

 but in a few regions of the cementum of the captive- 

 born specimen, WFP 670, there were twice as many 

 GLGs as in the dentine (Fig. 11), indicating that a 

 GLG may have been deposited twice a year in the 



cementum. In expanded regions of the cementum in 

 another specimen (ACM 104; see Table 2), the 

 cemental count was equal to the dentinal count; but 

 in thinner regions the cemental count was only half 

 that of the dentine, suggesting a cemental GLG being 

 deposited every 2 yr in some cases. 



Direct monitoring. — The results of examinations of 

 thin sections of the series of three teeth from each of 

 three live animals, taken at the beginning, at mid- 

 point, and at the end of a 1-yr monitored period are 



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