MALE GENITAL ORGANS 327 



1807). Rathke studied these "Oken's bodies" further, and found more accurately 

 their relation to the epididymis and ductus deferens. Miiller (Bildungsgeschichte der 

 Genitalien, 1830) wrongly declared that they do not form the epididymis; but he dis- 

 covered that "at the time when the Wolman bodies are most highly developed, the 

 germ of the ovary or testis lies on their inner side; and on their outer side, extending 

 even to their upper end, there is a duct which does not connect with the Wolman 

 bodies it appears to have arisen from their short and much stouter excretory duct." 

 He saw that this second duct, now known as the Miillerian duct, formed a part of the 

 uterine tubes. In fact it forms the entire tubes together with the uterus and vagina; 

 in the male it produces interesting vestigial structures which are constantly present in 

 the adult. 



The Miillerian duct arises as an outpocketing of the ccelomic epithe- 

 lium near the anterior end of the Wolffian body. The orifice into the 

 peritoneal cavity becomes surrounded by irregular folds known as 

 fimbria. As the Miillerian duct grows posteriorly by the elongation 

 of its blind end, it lies in contact with the Wolman duct as seen in Fig. 

 326, but the Wolffian duct does not contribute toward its formation. 

 The two Miillerian ducts reach the neck of the bladder side by side, 

 and acquire openings into it between those of the Wolman ducts. Near 

 the bladder the two Miillerian ducts fuse with one another so that their 

 distal part is represented by a single median tube, on either side of which 

 is a Wolffian duct (Fig. 306, B, page 311). In the female the united 

 portion becomes the vagina and uterus, and the separate parts are the 

 uterine (or Fallopian) tubes. In the male the united portion becomes a 

 small blind pocket, the prostatic utricle, opening into the prostatic urethra. 

 Each fimbriated extremity becomes transformed into the appendix testis, 

 and the remaining portion of the ducts, except for occasional fragments, 

 becomes obliterated. Thus only the two extremities of the Miillerian 

 ducts are ordinarily permanent in the male (Fig. 328). 



The genital glands in either sex begin as a thickening on the ventro- 

 medial border of each Wolffian body (Fig. 326). A section of this genital 

 ridge is shown in Fig. 303, C, page 307. The ridge is a dense mass of 

 mesoderm covered by the peritoneal epithelium, which here consists 

 of a syncytium very closely connected with the underlying tissue. Ac- 

 cording to Felix (Keibel and Mall's Human Embryology, vol. 2) everything 

 that is later developed within the genital ridge has a common origin from 

 the peritoneal epithelium. The ridge becomes filled with an epithelial 

 mass which then separates from the peritoneal layer. Beneath the peri- 

 toneum this mass produces the dense connective tissue capsule which sur- 

 rounds the testis, called, from its whiteness, the tunica albuginea; within 

 the genital ridge it is "quite suddenly" resolved into anastomosing cords 

 with looser tissue between them, and the cords become the tubules of the 

 testis. Allen, in an earlier account (Amer. Journ. Anat., 1904, vol. 3, 

 pp. 89-155), likewise finds that the cells of the peritoneum and the under- 



