20 



LIVE-STOCK JUDGING 



occurrence, except in rare instances, prohibits the sub- 

 sequent appearance of cestrum. 



26. Gestation. The duration of gestation is usually 

 correlated with the size and longevity of the species, being 

 three weeks in the case of the mouse and twenty-two 



FIG. 9. Generative organs of the mare, a, right ovary ; 6, right ovi- 

 duct ; c, right uterine horn ; d, left uterine horn ; e, body of the 

 uterus ; e\, vaginal part of uterus ; e^, mouth of uterus ; /, broad liga- 

 ment ; /i, suspensory ligament of the ovary ; / 2 , round ligament ; 

 g, vagina ; h, vulva ; i, vulvar cavity ; i\, posteri or commissure ; 

 *2, anterior commissure ; A;, muscle constrictor cunni ; ra, corpus 

 cavernosum vestibule ; n, abdominal wall ; o, left kidney ; p, left 

 ureter ; r, bladder ; s, urethra ; t, rectum ; u, anus ; v, external sphinc- 

 ter muscle of anus ; w, point where the levator ani muscle passes 

 under the external sphincter ; x, levator ani muscle ; y, longitudinal 

 fibers of the rectum ; y\, posterior band of fibers ; z, muscle constric- 

 tor vestibule; 1, utero-ovarian artery; li, branch to the ovary; 

 12, branch to the horn of the uterus ; 2, external uterine artery ; 

 3, umbilical artery ; 4 and 5, sections through pelvic bone. 



months in the case of the elephant. There is established 

 following conception, and through the medium of a special 

 development of the walls of the pregnant uterus and of 

 the membranes enveloping the embryo, a temporary cir- 

 culatory system, by means of which the constituents of the 



