Histology of accessory sex organs and extragonadal sperm reserves in the male hopping mouse Notomys alexis.

In the hopping mouse, Notomys alexis, there are very small testes and relatively low numbers of spermatozoa in the extragonadal ducts. Large ventral prostates are present, but the seminal vesicles, coagulating glands, ampullaries, and dorsal prostates are all extremely small, although their histological structure and secretory activity is similar to that of the laboratory murids. Bulbourethrals are typical, but the preputials are very small and composed of sebaceous secretory units and an associated hair follicle. The possible functional significance of these findings is briefly discussed.