Bull. U. S. B. F. 1912. 
Plate LVIII. 
Fig. 5. — Redrawn from Maurer, 1886. Thyroid of a trout 20 cm. long; shown in its relation to the branchial arteries, 
seen from the ventral side. 
Fig. 6. — Redrawn from Maurer. Median section to show distribution of thyroid about the ventral aorta in a trout 2.5 
cm. long. 
Fig. 7. — Redrawn from Maurer. Cross section of the head of a trout embryo of 30 days, showing earliest evagination 
of pharyngeal epithelium to form the thyroid. 
Fig. 8. — Redrawn from Maurer. Median section through head of trout embryo of 35 days. Primary thyroid vesicle 
(/) still attached to parent epithelium by pedicle. 
Fig. 9. — Redrawn from Maurer. Cross section of a trout embryo of 35 days. Primary thyroid vesicle (/) separated from 
parent epithelium. 
Fig. 10. — Redrawn from Maurer. Median section through head of trout embryo of 41 days. Compared with figure 8, it 
shows that the elongated primary thyroid vesicle (/) has moved backward and now lies ventral to the aorta. 
Fig. 11. — Drawing showing gross appearance of jugular pit from below. 
