CHAPTER XII 



THE MALE GENERATIVE ORGANS 



The siierinatozoa or conjugating cells produced by the male 

 are de\^eloped in the testicles which are therefore the essential 

 reproductive organs m that sex, just as the ovaries which produce 

 the ova are the essential reproductive organs in the female sex. 

 The epididymis, vas deferens, urethra and penis which are in- 

 strumental in convejdng the spermatozoa to the exterior, together 

 with the various glandular structures which communicate with 

 them, may be described as the accessory male generative organs. 



The Testicle. In man and in all the domesticated animals 

 the testes (or testicles) are a pair of glands lying outside of the 

 body cavit}' in the scrotum which is situated posteriorly between 

 the anus and the urogenital opening. The scrotum consists of a 

 pair of pouch-like sacs communicating with the body cavity by 

 the inguinal canals through which the spermatic cords and vasa 

 deferentia pass. The spermatic cords contain the blood vessels 

 and nerves which supply the testes, and the vasa deferentia are 

 the ducts which convey the testicular secretion to the urethra or 

 common urogenital canal. 



In the lowest group of mammals (Monotremata) the testes 

 remain in the body cavity always as they do in birds. In Insecti- 

 vora (e.g. the mole) the testes descend periodical!}^ into temporary 

 receptacles, and there is no true scrotum. In many rodents the 

 testes after descending into the scrotixm at the commencement of 

 rut are withdrawn into the body cavity at the end of the jDcriod. 

 In most other animals the testes after descending into the scrotum 

 during early life (and generally before birth) remain there per- 

 manently, but it is noteworthy that in the ram after tupping the 

 organs apparently become smaller and tend to be drawn upwards 

 without however passing into the cavit}^ of the aljdomen. 



Each testis is surrounded by a serous membrane (the tunica 

 vaginalis) within which is a fibrous capsule (the tunica albuginea). 

 Posteriorly the fibrous capsule is jirolonged into the interior of the 

 gland to form the mediastinum testis. The greater part of the 



