THYREOID GLAND OF THE TELEOSTS 



743 



Fig. 3. Sections through the thyreoid gland of Brevoortia, all anterior to the 

 aortic bifurcation. 



the aortic bifurcation and the posterior end is at the second 

 branchial arch, (pi. I, fig. 3). 



The floor of the pharynx is very narrow, thus there is no chance 

 for a lateral extension and the thyreoid follicles become dis- 

 persed only in a dorso-ventral direction. This extension is 

 sometimes 4 mm. high (fig. 3). 



