THE NECTURUS 51 



face__tliat is inclined mesially and dorsally. It is difficult 

 to see because of its similarity to the cartilaginous material 

 on which it lies but the follicular structure will distinguish 

 it from cartilage. The thyroid is about 5 mm. long and 

 2 mm. wide with a thickness of about a millimeter. Care- 

 fully remove the disc and place in a watchglass for obser- 

 vation under a X 15 magnification. If desired it can be 

 dehydrated, stained and cleared. If prepared slides are 

 available, more of the structures can be shown. Note the 

 large follicles lined with a single layer of cells and full 

 of colloid material. Count the number of follicles. 



