876 THE OENEBATIVE APFABATUS. 



(Beneatli the liilus of the ovary, and between the layers of the broad 

 liaament and the round ligament, is found a small body, usually described 

 as the parovarium, consisting of a number of fine tubes with blind extremities. 

 It is considered as the remains of the Wolffian body : a foetal structure that 

 forms the epididymis in the male, and has been named the organ of Bosen- 

 muller in the female. Chauveau does not mention its existence in the 

 domesticated animals, though Leyh does.) 



2. The Oviducts, or Fallopian or Uterine Tubes. (Fig. 411, 2.) 



The uterine tube is a little flexuous canal, lodged in the broad ligament, 

 near its anterior border. It commences at the ovary by a free, expanding 

 extremity — the pavilion of the tube (or ostium abdominale), and terminates 

 in the cul-de-sac of tue uterine horn by opening into it (the ostium uterinum). 

 Its canal at the middle is so narrow as scarcely to admit more than a very 

 thin straw, and its calibre is still less towards the uterine extremity ; near 

 the ovary, however, it is wide enough for the passage of a thick goose-quill. 



The orifice of the uterine extremity opens in a small and very hard 

 tubercle. The ovarian extremity, in all mammalia, offers a very remarkable 

 arrangement. It opens into the peritoneal cavity, near the fissure of the 

 ovary, and in the centre of the expansion named the pavilion of the tube, 

 which is also designated the fimbriated extremity (or morsus diaholi). 

 This pavilion is attached to the external side of the ovary, and has a very 

 irregular outline : notched as it is into several lancet-shaped, unequal pro- 

 longations (fimbriae), which float freely in the abdomen. Here are, then, 

 two important anatomical facts : the discontinuity between a gland and 

 its excretory canal, and the communication of a serous cavity with the 

 exterior. 



Structure. — The oviduct is formed of a serous, a contractile, and a 

 mucous tunic. The serous (external) is furnished by the broad ligament, 

 and is derived from the peritoneum. The contractile (middle) is constituted 

 by unstriped muscular fibres, which extend into the pavilion. (They are 

 arranged as circular — internal, and longitudinal — external fibres, and are con- 

 tinuous with those of the uterus ; they are mixed with immature nucleated 

 areolar tissue.) The mucous membrane is in longitudinal folds in the tube, 

 but in the pavilion these folds are radiating ; it is covered by a ciliated 

 cylindrical epithelium (the vibrations of the cilia being towards the uterus.) 

 (It has very few glands and no villi.) At the margin, or fimbrise, of the 

 pavilion it suddenly ceases, and is continued by the peritoneum (a serous 

 cyst is frequently found in this situation ; at the other extremity the 

 mucous membrane is continuous with that of the uterus). 



Functions. — The excretory duct of the ovary, the uterine tube, seizes 

 the ovulum expelled from the ovisac, and carries it to the uterus. It is 

 therefore necessary that, at the moment of rupture of the ovisac, the fimbriae 

 should be applied to the ovary, in order to receive the germ and bring 

 it to the abdominal orifice of the tube. The application of the pavilion to 

 the ovary is brought about either by the contraction of the muscular fibres 

 it contains, or through the distention of the bulb of the ovary. Some- 

 times this mechanism is insufficient, and the ovulum falls into the abdominal 

 cavity, becomes fixed there, and is developed if it has been previously fecun- 

 dated; this occurrence constitutes the most remarkable variety of extra- 

 uterine gesfc<ation. 



The oviduct also conveys the seminal fluid of the male to the ovulum. 



