abnormal seminal vesicle morphology abnormal reproductive system development abnormal seminal vesicle development MP:0013317 MPheno.ontology The seminal vesicles are present as branched organs in many mammals including mice and humans. However, the seminal vesicles are completely absent from some mammals including monotremes, marsupials, carnivores, and cetaceans. In addition, the seminal vesicles in some mammals such as the guinea-pig are present as unbranched tubular glands. aberrant or incomplete differentiation of either of the paired sac-like glandular structures situated posterolateral to the urinary bladder in the male and functioning as part of the reproductive system; seminal vesicles develop from the segments of the Wolffian ducts immediately adjacent to the urogenital sinus abnormal gonecyst development abnormal seminal gland development gonecyst dysgenesis seminal gland dysgenesis seminal vesicle dysgenesis