192 



JEREMIAH S. FERGUSON 



O 





o ^^ 



B 



Fig 13. Outline of the follicles of thyroid glands as seen in total mounts A 

 from Mustelus canis, X 152. B, from Squalus acanthias, X 152 C from Car- 

 charias litoralis, X 152. D, from Raia erinacea, X 80 



various species. I have tabulated the results of some of the meas- 

 urements. 



SPECIES 



Mustelus. . 

 Squalus. . . , 

 Carcharias 

 Raia 



MAXIMUM 



DIAMETER OF 



FOLLICLE 



MINIMUM AVERAGE 



DIAMETER OFDIAMETER OF 



FOLLICLE FOLLICLE 



.160mm. 

 .079 

 .273 

 .340 



.017mm. 

 .013 

 .023 

 .053 



.067mm. 

 .047 

 ,100 

 .167 



AVERAGE 



LENGTH OF 



FISH 



67.8cm. 

 53.7 

 117.2 

 46.2 



RATIO 



FOLLICLE TO 



FISH 



101.7 



115. 



117.2 



27.7 



AVERAGE 



DIAMETER 



THYROID 



GLAND 



13.6mm. 

 no data 

 13.7 

 6.5 



