. The chordates. Chordata. Mammalia: Visceral Systems -OVARIAN LIGAMENT. -OVARY. 655. Fig. 495. The human female urinogenital system. (After Sobotta. Courtesy, Neal and Rand: "Chordate Anatomy," Philadelphia, The Blakiston Company.) and body-wall. In the case of the testis, a specialized agent plays an important part in the later phase of the "; At an early period in the development of the testis a peritoneal fold becomes transformed into a ligament stretching from the hind end of the testis to that particular spot in the posterior abdominal wall where the scrotum i
. The chordates. Chordata. Mammalia: Visceral Systems -OVARIAN LIGAMENT. -OVARY. 655. Fig. 495. The human female urinogenital system. (After Sobotta. Courtesy, Neal and Rand: "Chordate Anatomy," Philadelphia, The Blakiston Company.) and body-wall. In the case of the testis, a specialized agent plays an important part in the later phase of the "; At an early period in the development of the testis a peritoneal fold becomes transformed into a ligament stretching from the hind end of the testis to that particular spot in the posterior abdominal wall where the scrotum is destined to develop. After the scrotum has been formed, this ligament, the gubernaculum, is found to be attached to the posterior wall of the scrotum (Fig. 493) and external to the tunica vaginalis. By some obscure process this gubernacular Ligament (not muscular) shortens and in so doing pulls the testis into the scrotum, thus completing the "; The advantage which accrues to a mammal in possessing a scrotum is far from obvious. A testis which normally resides in a scrotum ceases to produce spermatozoa if it remains in the abdominal cavity. Crypt- Fic 194.—(Continued.) surface of the expanding bladder. The mesonephric ducts in the male, serving as the spermatic ducts, retain their openings into the urinogenital sinus which becomes extremely contracted and elongated to form the urethral canal of the penis (see Fig. 492), while the Mullerian ducts degenerate. In a female, shown in (D) and (E), the mesonephric ducts degenerate and, as the ureters are carried forward onto the bladder, the oviducts retain their connection with the urino- genital sinus which appears as the vestibule of the adult. (E) shows a common adult condition—the posterior regions of the two oviducts joined to form a median vagina into which open right and left uteri (see also Fig. 495).. Please note that these images are extracted from scanned page images that may have been digitally e
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