Diseases of the lower parts of the urinary tract are not numerous and of incidental interest only; many are associated with or due to lesions in the genital organs, and will be referred to later. Cystitis is uncommon, only being observed some four times unrelated to prostatitis and vesiculitis. Two of these cases were secondary to a traumatic urethritis. No stones have been seen. A mixed cell sarcoma was found springing from the bladder wall in a Richardson’s Kangaroo Rat (_Perodipus richardsoni_). The written record has unfortunately been lost, but the preserved slide confirms the original diagnosis. Rupture of the bladder occurred in a Gray Fox with stenosis of the end of the penile urethra causing retention and secondary cystitis. Another stricture of the urethra in an Ocelot (_Felis chibigonazon_) caused great dilatation of the bladder. This animal is thought to have chewed off all the external genitalia because of lice, with the result that the stump of the urethra became involved in a contracting cicatrix. Opossums, raccoons and wild dogs have shown light cases of urethritis seemingly traumatic in origin, and two dogs had cystitis and urethritis associated with what was believed to be distemper. SECTION IX THE FEMALE REPRODUCTIVE ORGANS The mechanism and organs of reproduction differ so widely in the classes under discussion that it will be necessary to describe separately the alterations in mammals and in birds. Examples of abnormality and disease are not very numerous and I shall cite cases for many of the conditions rather than prepare comparative lists as has been possible in many foregoing sections. Some years ago Dr. Edward A. Schumann[40] studied the comparative anatomy and physiology of the mammalian female generative organs, and I shall condense and paraphrase his work. (The complete articles may be found as in the references below.) This gentleman, because of his gynecological experience and broad interest in comparative biology, has been consulted whenever unusual material from this tract has presented itself so that many of the descriptions that I shall employ are due to him. I take this opportunity to acknowledge with thanks his interest and helpfulness. COMPARATIVE ANATOMY IN EXPLANATION OF HUMAN UTERINE ANOMALIES.