An angiographic study of the fox testis in various stages of sexual activity.

The arteries and veins of the fox testis were studied using an angiographic technique. The postnatal development of the testis involved only minor modification of the vasculature. In the non-breeding season both the arteries and veins of the adult fox testis undergo extensive spiralization which completely disappears during the breeding season. When the sequence of morphological changes in blood vessels are related to available data on changes in testicular size, blood flow and connective tissue content, it is obvious that the vascular spiralization is passive and related to shrinkage of the organ and dose not primarily influence the testicular blood flow.