EightTriturus cristatus Laur.adult ♀ ♀ were treated with testosterone prnprionale after castration. The development of male sexual secondary characters as previously demonstrated by De. Beumont (1929) by means of testicular implants, was observed. The following structural changes were furthermore evidenced by the present investigation: 1) changes in the shape and size of the cloacal cavity and cloacal papilla. 2) inhibition of keralinization in the epidermis, and its suhstitution by a pluristratified columnar epithelium. typical of ♂ ♂, at the level of the cutaneous processes bordering the posterior end of the cloacal cleft. Such epithelium gives origin to both cutaneous glands and abdominal glands. 3) Functional activity is detectable in the tubules of the abdominal gland. Some segments are distended with secretion into conspicuous sacs. They develop in length as far as the lumbar region. 4) The uniformcly mucous secreting cells lining the cloacal chamber in the normal ♀ differentiate into a ciliated epithelium at the level of the dorsal groove, and into both ciliated and goblet cells along the side walls. They undergo, therefore, the same ‘modulation’ taking place in the ♂ cloacal epithelium at the time of functional awakening after the quiescent period at each annual cycle. 5) In the pelvie gland, which differentiates from the ‘recepta-culum scminis’, three types of tubules are demonstrable, according to their size, stainability of the secretion granula, and site of origin. The medial ones are seen to reach the region of the lumbar kidney.