[Seasonal changes in the testes of the silver fox]

In 14 mature male silver foxes in spring and autumn by means of counting dots and transsections, relative and absolute summational volumes and areas of the seminiferous tubule surfaces, interstitial glandulocytes (Leydig's cells) and stroma have been calculated. Average diameter and total length of the tubules have been determined. Increased mass of the testes in spring is the result of a proportional enlargement of the total volume of the seminiferous tubules and stroma, while the total volume of the endocrinic part in the organ changes insignificantly. The increase of the total volume of the seminiferous tubules occurs at the expense of the increasing diameter, though their total length remains the same.