CHAPTER V. The Evidence of the Thyroid Gland

THE EVIDENCE OF THE THYROID GLAND

The value of the appendage-unit in non-branchial segments--The double nature of the hyoid segment--Its branchial part--Its thyroid part-- The double nature of the opercular appendage--Its branchial part--Its genital part--Unique character of the thyroid gland of Ammocoetes-- Its structure--Its openings--The nature of the thyroid segment--The uterus of the scorpion--Its glands--Comparison with the thyroid gland of Ammocoetes--Cephalic generative glands of Limulus-- Interpretation of glandular tissue filling up the brain-case of Ammocoetes--Function of thyroid gland--Relation of thyroid gland to sexual functions--Summary 185