MYRICK ET AL.: DENTAL LAYERS IN HAWAIIAN SPINNER DOLPHINS 



200|jm 



N 



100pm 



D 



Treatments 



1975 1976 



I i I i I I i I II i I ll I I I I 



1977 



1978 



labels 



I Ml I M I I I I I L UU J I I I I I I I m^J I I III 



1979 



l i I I I I I 



Treatments to otners 

 in same tank 



\ ABC 



v Neonatal line 



D E 



FG\. 



PC 



FIGURE 7.— Teeth from dolphin carcass WFP 670 (captive-born animal). A. Untreated thin section showing TCL labels in den- 

 tine. Labels A-B apparently represent TCL imparted to this animal through its mother's milk (UV, 39X). N =neonatal line; PC = 

 pulp cavity margin. B. Portion as shown in 1A showing numerous labels from TCL-dosed smelt stolen from other dolphins 

 occupying the same tank. Labels F and G represent direct treatments administered shortly before death (UV, 150X). C. Thin- 

 sectioned tooth showing three entire and one partial GLGs (indicated by heavy dark marks) in the postnatal dentine as inter- 

 preted from TCL labels. LMLs are indicated by fine dark markers (plain transmitted light, 150>^. D. Chart showing dates of 

 direct and presumed incidental introduction of TCL and corresponding labels identified in the dentine by relative label position 

 and thickness. 



217 



