Plate PXIII. 
Fig. 19. — Uoinesticated Scotcli sea trout finserling-; normal tliyroid structure. X86. 
Fig. 20. — Domesticated Scotch sea trout fing-erlingr; same liatchery as above, showing simple hyperplasia, increased 
number of thyroid follicles; epithelium high cuboidal and low columnar; colloid diminished. X86. 
