DEVELOPMENT OF THE UKO-GENITAL OBGANS 



1327 



The blood-supply of the bulb is derived, on each side, from the arteria bulbi vestibuli, 

 a branch of the internal pudendal. 



GLANDULE VESTIBULARES MAJORES. 



The greater vestibular glands (O.T. glands of Bartholin) are placed one on 

 each side of the lower part of the vagina, and represent the bulbo-urethral glands in 



US URINARIUS. 



UB. 



^-TR I ANGULAR [FASCIA INFERIOR OF 



LIQT UROGENITAL DIAPHRAGM] 



Larger vestibular glands V 

 , Vagina 

 Central point of perineum 



FIG. 1036. DISSECTION OP FEMALE PERINEUM TO SHOW THE CLITORIS, THE BULB OF THE VESTIBULE, 

 AND THE LARGER VESTIBULAR GLANDS (D. J. Cunningham). 



the male. They are often overlapped by the posterior ends of the bulbus vestibuli, 

 and are covered by the bulbo-cavernosus muscle. Each is about the size and 

 shape of a small bean, and possesses a long slender duct which opens into the 

 rima pudendi in the angle between the attached border of the labium minus and the 

 vaginal opening. 



DEVELOPMENT OF THE URO-GENITAL ORGANS. 



THE URO-GENITAL PASSAGES. 



General Account. In tracing the developmental history of the uro -genital 

 passages we may for convenience begin with an embryo of fifteen days old. About this 

 1 time a duct, which runs in a longitudinal direction, and occupies a position on the lateral 

 side of the proto vertebral somites, begins to develop on each side of the body. With the 

 exception of the anterior portion of the cloaca and the proximal part of the allantois, this 

 duct, which has received the name of primary excretory or Wolffian duct, is the earliest 

 formed structure from which, or in connexion with which, the parts of the adult 

 urine-genital system arise. 



The Wolffian duct serves as the canal, or duct, for the primitive secretory organs 

 the pronephros and the mesonephros of the embryo. With the atrophy of these the 

 ! duct suffers modification, yet both sexes in the adult possess structures which have 

 their embryonic origin from the Wolffian duct. In the male the duct of the epididymis, 

 the ductus deferens, and the ejaculatory duct, are to be looked upon as directly developed 

 from the Wolffian duct of the embryo ; while in the female the longitudinal duct of 

 the ep-oophoron and the appendices vesiculosi are rudimentary structures having a like 

 origin. Further, the ureter and its pelvis arise in both sexes as an outgrowth from the 

 Wolffian duct (Fig. 1037). In the male the vesicula seminalis is developed as a diverti- 

 culum of the Wolffian duct. 



The primitive secretory organs, the pronephros and the mesonephros, develop in 

 lexion with the anterior part of the Wolffian duct (p. 48), and, during the early life 

 the embryo, the latter of these is a most important structure. Even in the embryo 



