The anatomy and histology of the female reproductive tract in Dendrolagus matschiei and D. ursinus are described and compared with the previous brief accounts of the anatomy in D. inustus.

There is considerable variation in the degree of development of the lateral vaginae; this may be specific, but is more probably a function of age and sexual activity. The median sinus vaginalis extends caudally to the caudal junction of the lateral vaginae, and ends blindly in the tissue of the urinogenital strand ventral to that junction, and a little cranial to the urethral meatus. There is a short common vagina, and a comparatively long urinogenital canal. The uteri open into the upper ends of the lateral vaginae through conspicuous papillae on their dorsal walls. The ovaries are contained in peritoneal pouches formed in the ligamentum latum genitale, and the abundant fimbriae cover the mouths of the ovarian sacs thus formed. Histological examination of the various parts of the reproductive tract shows that the primitive circular muscular coat forms the greater part of the walls of the uteri and of the lower parts of the lateral vaginae, and that only in the sinus vaginalis do the longitudinal fibres form a complete coat in addition to that formed by the circular ones. The ovary shows a complete lack of interstitial tissue, but a large amount of luteal atresia. The structure of the follicle and of the corpus luteum atreticum is described, and the possible method of formation of the latter is discussed in the light of the studies of other workers.