Abstract
The secretory activity of the SCO cells ofLacerta s.sicula Raf. is strongly reduced during the winter. Such reduction is documented by the decrease of the number of secretory granules type A and B described in previous papers in the summer SCO cells. Also the sacks of RER filled with electron-dense material (type C secretion) are very few; in their place there are, in the basal region of the cells, large vacuoles. In the distal region of the cells, at the free cell surface, a pronounced increase in the number of microvilli is noticed.