AbstractThe study aimed to characterize the ultrastructure of components of the sperm pathway in Galea spixii (Spix's yellow-toothed cavy) at different stages of sexual development. Segments of the epididymis and vas deferens of 10 Galea spixii were studied using scanning and transmission electron microscopy. Principal and basal cells with similar characteristics were seen in the epididymis and vas deferens. Both cell types are responsible for maturation of sperm as well as the ability to fertilize and reabsorption. The post natal morphological development of the epididymis and vas deferens was similar to testicular development of the species.