. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Progressive development of vesicles of testis of Squalus cornubicus. a, portion of duct with a few nucleated cells, the primary or germinal cells of the future acini, at- tached to its walls ; b, c, d, e, f, primary cells, or acini, in successive stages ; g, one of the secondary cells in an immature state; h, a secondary cell elongated into a cylinder, each cell of its com- posite nucleus elongated into a spiral ; i, k, the spiral cells or spermatozoa free. {After Goodsir.) cleated cells, and situated mare towards the su
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Progressive development of vesicles of testis of Squalus cornubicus. a, portion of duct with a few nucleated cells, the primary or germinal cells of the future acini, at- tached to its walls ; b, c, d, e, f, primary cells, or acini, in successive stages ; g, one of the secondary cells in an immature state; h, a secondary cell elongated into a cylinder, each cell of its com- posite nucleus elongated into a spiral ; i, k, the spiral cells or spermatozoa free. {After Goodsir.) cleated cells, and situated mare towards the surface of the lobe (c). 5th, The full sized vesicles situated at the surface of the lobe, with their contents in various stages of deve- lopment (d, e, f). These vesicles are spheri- cal and perfectly closed ; that part of the wall of each, which is attached to the hollow pedicle, forming a diaphragm across the pas- sage, so that the vesicle has no communica- tion with the ducts of the gland. The con- tained cells are at first spherical (g) ; but as the spermatozoa are gradually formed within them, they present a cylindrical form (//), and they are arranged within the vesicles in somewhat of a spiral manner (/'). When the development has advanced to this stage, the diaphragms across the necks of the vesicles dissolve away or burst; and the bundles of spermatozoa float along the ducts of the gland, some of them separating into indivi- dual filaments (i, /i). Besides the bodies now described, Prof. Goodsir has observed what he considers to be vesicles which have discharged their contents, and which are in a state of atrophy (.fig- 322. a). The testis of Sqiinlus cornubicus, the func- tional history of which has been now given, is considered by Prof. Goodsir as a type of a number of glands, whose action takes place after the same manner; and he lays down the following general facts, which he has ascer- tained in regard to glands of this order. " 1st, The glandular parenchyma
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