THE EXTERNAL GENITALIA 



229 



Fig. 238. — Diagrams to show the devel- 

 opment of male and female generative organs 

 from a common type (Allen Thomson). 



A . Diagram of the primitive urogeni- 

 tal organs in the embryo previous to sexual 

 distinction. 3, Ureter; 4, urinary bladder, 5, 

 urachus; ot, genital ridge from which either 

 the ovary or testicle is formed; ir, left 

 mesonephros; w, w, right and left mesonephric 

 ducts; m, m, right and left Miillerian ducts 

 which unite and course with the mesonephric 

 ducts in g.c, the genital cord; ug, urogenital 

 sinus; /, lower intestine; cl, cloaca; cp, phallus 

 which becomes clitoris or penis; Is, fold of 

 integument from which the labia majora 

 are formed. 



B. Diagram of the female type of sex- 

 ual organs. 0, Left ovary; po, epoophoron; 

 W, scattered remains of caudal mesoneph- 

 ric tubules (paroophoron); d G, remains of 

 the left mesonephric duct (canal of Gartner) 

 represented by dotted lines; that of the 

 right side is marked w; f, abdominal open- 

 ing of the left uterine tube; m, uterine tube 

 of the right side; u, uterus; g, round liga- 

 ment, corresponding to gubernaculum in 

 part; i, lower intestine; va, vagina; h, 

 situation of the hymen (MuUer's tubercle); 

 C, vestibular gland (of Bartholin), and im- 

 mediately above it the urethra; cc, corpus 

 cavernosum clitoridis; sc, corpus cavernosum 

 of clitoris; n, nympha; /, labium; ii, vulva. 



C. Diagram of the male type of sexual 

 organs, t, Testicle in the place of its original 

 formation; e, caput epididymidis; vd, ductus 

 deferens; W, scattered remains of the meso- 

 nephros, constituting the organ of Giraldes, 

 or the paradidymis; vh, vas aberrans; m, 

 Mullerian duct, the upper part of which 

 remains as the appendix testis, the lower 

 part, represented by a dotted line descend- 

 ing to the prostatic utricle, constitutes the oc- 

 casionally existing cornu and tube of the va- 

 gina masculina; g, gubernaculum; vs, vesicula 

 seminalis; pr, prostate gland; C, bulbo- 

 urethral gland of one side; cp, corpora 

 cavernosa penis cut short; sp, corpus caver- 

 nosum urethra;; s, scrotum; f, and the 

 dotted lines above, indicate the path of 

 descent of the testis and epididymis from 

 the abdomen into the scrotum whereby the 

 ductus deferens, vd, becomes looped over 

 the ureter, 3. 



P' f 



Fig. 238. 



