50 RECORDS VOLUME XI, MARCH, 1919. 



In the Cor}' Gannet, as previously said, 

 there is no indication whatever of the singu- 

 lar organism, which I have termed the thy- 

 mus, adhering to the syrinx, but there is a 

 vestigial thyroid gland present attached to 

 the single (left) carotid artery. This is a 

 small, eliptical body about .25 long and lies 

 on the inside of the carotid, fig. 4, A, being 

 the carotid artery; c, the thyroid gland; H, 

 the heart; u, w, x, and z, other arteries. The 

 thyroid I have called vestigial, for, judging 

 from its small size, it must be wholly func- 

 tionless. In a young Great Blue Heron T 

 found two thyroids, one adhering to each 

 carotid artery, but the left thyroid was near- 

 ly twice the size of the right, and in it were 

 some well developed, cylindrical glands each 

 of which was fastened by its inner termina- 

 tion to the outside of a small tubular vessel 

 that passed through the thyroid. 



The right thyroid of this heron also had 

 a small blood vessel passing through it, but 

 1 could find no developed glands. 



