Cytological studies on the spinning glands of platyphylax designatus walker (Trichoptera): Respective rôles played by the nucleus and the golgi apparatus during secretion

In sections the protoplasm of the spinning gland of Platyphylax designatus Walker appears to be a syncytium with large, branching nuclei, which contain both nucleoli and chromatin granules embedded in a delicate linin reticulum. In the normal gland the nucleus is sharply marked off by a nuclear membrane from the granular, homogeneous cytoplasm. The Golgi apparatus appears as rings, loops, or comma‐like structures, evenly distributed and without orientation to the nucleus or lumen of the gland. The nucleoli first increase both in number and size within the nucleus, then migrate out into the cytoplasm, where they undergo further growth, and finally are dissolved and passed out into the lumen of the gland as liquid secretion. Small vacuoles appear near the periphery of the gland in early periods of activity. In glands active for forty‐eight hours all stages of the secretory process may be seen. In glands active for longer periods only vacuoles are present which we interpret as the remains of the secretory inclusions. There is a progressive decrease in the nuclear content of the nucleus. Throughout the activity of the gland the Golgi apparatus changes little from the normal condition, both in form and distribution. As activity progresses, the bodies become smaller and slightly more dispersed. No relation of Golgi apparatus to the secretory phenomenon is apparent.