DEVELOPMENT OF THE URINARY AND SEXUAL ORGANS. 



997 



and the Wolffian duct in man becomes the vas deferens (///, V) , together with 

 the seminal vesicle. According to Sernoff, Bornhaupt, Egli and Biegelow, autoch- 

 thonous strands of cells develop within the sexual gland of man and these are 

 transformed into the seminal ducts, and later communicate with the Wolffian 

 ducts. 



The Mullerian ducts (the true excretory ducts of the sexual glands) undergo 

 atrophy in man, with the exception of the lowermost portion, which becomes 

 the masculine utricle or the prostatic vesicle (///, u); this is the analogue of the 

 uterus. In carnivora and ruminants the Miillerian ducts attain a greater size, 

 to form a rudimentary vagina and a uterus bicornis; in rare cases a true, small 

 uterus has also been found in man. The upper tubules of the Wolffian body 

 unite in the third month with the sexual gland, and become the coni vasculosi 

 of the epididymis, which is furnished with ciliated epithelium () ; the remaining 

 portion of the primitive kidney undergoes atrophy. A number of detached 

 tubules become the vasa aberrantia (a) of the testicle. The pedunuculated 

 hydatid of Morgagni (ti) at the head of the epididymis is, according to v. Luschka, 

 Becker, and M. Roth, a constricted-off vesicle of the epididymis, occasionally 

 containing semen and lined by ciliated epithelium; according to Waldeyer it is 

 the homologue of the infundibuliform portion of the oviduct, while according to 

 Toldt it is derived from the abdominal extremity of the duct of Muller. The 



FIG. 392. Development of the Internal Organs of Generation. /, Undifferentiated stage: D, sexual gland 

 lying upon the tubules of the Wolffian body; W, Wolffian duct; M, duct of Muller; S, urogenital sinus. 77, 

 Transformation into the Female type: F, fimbria with the hydatid (& 1 ); T, oviduct; U, uterus; 5, urogenital 

 sinus; O, ovary; P, parovarium. 777, Transformation into the male type: H, testicle; E, epididymis, with 

 the hydatid (h); a, vas aberrans; V, vas deferens; S, urogenital sinus; u, utriculus masculinus; 4 d, end-gut; 

 a, allantois; , urachus; K, cloaca; 5 M, rectum; m, perineum; b, rudimentary bladder; S, urogenital sinus. 

 (Diagrammatic.) 



organ of Giraldes (convoluted tubules with ciliated epithelium) at the upper 

 extremity of the testicle is probably also a vestige of the Wolffian body. The 

 Wolffian duct itself becomes the vas deferens (V), together with the seminal 

 vesicle (as an outgrowth). The two Wolffian and the two Mullerian ducts lie 

 close together at the pelvic inlet in a cord (genital cord). Later, when the Mul- 

 lerian ducts have undergone atrophy, the seminal ducts formed from the Wolffian 

 ducts become more widely separated. 



In the female sex, the tubules of the primitive kidney, with the exception 

 of a vestige within ciliated tubes (parovarium or Rosenmuller's organ) and a portion 

 in the broad ligament resembling the organ of Giraldes, undergo atrophy (II, P); 

 as do also the Wolffian ducts; although they are still visible in fetuses of five 

 months, but downward only as far as the region of the vaginal vault; below 

 this and toward the urethral orifice they disappear completely. Diminutive 

 vestiges of the ducts are often found anteriorly and laterally embedded in the 

 uterine and vaginal muscularis, chiefly on the right. They persist permanently 

 in ruminants, the horse, the pig, the cat, the fox, as Gartner's ducts; in man 

 they may give rise to pathological cyst-formation. The Mullerian ducts become 



