. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 1110 THYROID GLAND. refer to the observations, so far as they go, as free from any material error. In the Skate I have found the organ described by Retzius as a salivary gland, and by Mr. Simon as a thy- roid, occupying the situation well described by the latter, and lying exactly upon the terminal division of the branchial aorta. It was of a faint reddish gray tint, and presented to the unaided eye the appearance of a conglomerate gland. No excretory duct, however, was ob- served proceeding from it. In structure it cons
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 1110 THYROID GLAND. refer to the observations, so far as they go, as free from any material error. In the Skate I have found the organ described by Retzius as a salivary gland, and by Mr. Simon as a thy- roid, occupying the situation well described by the latter, and lying exactly upon the terminal division of the branchial aorta. It was of a faint reddish gray tint, and presented to the unaided eye the appearance of a conglomerate gland. No excretory duct, however, was ob- served proceeding from it. In structure it consisted of numerous vesicles aggregated to- gether. The form of these was mostly circular; some were elongated, and many variously altered by mutual pressure. Their diameter was about Ti^ to JT inch (fig. 744-. A). The limiting envelope of the vesicles presented a Fig. 745. Fig. From thyroid of Skate. A. Vesicle, -f'y in. in diameter. B. Several of the nuclei imbedded in diffused mottled substance. good example of homogeneous membrane. It was lined internally by a pretty thick stratum of epithelial substance, which in some instances was so abundant as almost to fill up the cavity. The epithelium consisted of nuclei and a very large quantity of rather coarse granular ma- terial, which quite obscured the nuclei them- selves (fig. 744. B.) There were also a few granular cells, and, in the interior of many of the vesicles, imperfect prismatic or octohedral crystals could be discerned. I could not discover, among the glandular structure, any tubes resembling excretory ducts; so that I am much inclined to believe it has no relation to the salivary organs, but belongs to the class of ductless glands. A gland, however, it assuredly is, and not a mere vaso-ganglion. Besides this body I discovered at some dis- tance behind it, just at the junction of the branchial arches anteriorly, a small light red- dish mass, which was covered in by a thin fascia, and by the mucous membrane, and
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