IMKRX.IL <>/:i;A.\S oF dEyKllATlnX. 61 



The veins are extremely large, and form a very close plexus around the 

 f;land {bulb of the ovarij), emptying themselves into the vena cava near 

 the renal veins. The lymphatics pass to the suhlumbar ganglia, and 

 the nerves come from the small mesenteric plexus. 



Differences. 



Coxv, Sheep, and Chat. 



In the Cow the ovaries are relatively smaller than in the Mare, but 

 their form and structure are the same. Each is lodged in a depression 

 or sacculus of the broad ligament, which is more or less deep, and the 

 Ciraafian vesicles are visible through the tunica albuginea. The same 

 arrangement is observable in the Sheep and Goat. 



Pi'J- 

 In the Pig the ovaries are comparatively large, oblong bodies, with 

 an irregular, tuberculated, or lobulatcd aspect, due to the Graafian 

 vesicles, which, when well developed, project beyond the surface of the 

 organ, instead of remaining within it. When these ovisacs enlarge, 

 the stroma is scanty in proportion. Tiach ovary is enclosed within a 

 peritoneal sac, near tlie opening of which it has a pedunculate attach- 

 ment. The posterior wall of this sac, as we have seen, appears to be 

 formed l)y the wide and deep pavilion of the Fallopian tube. 



Bitch and Cat. 

 There is nothing particular to indicate in the ovaria of the Bitch and 

 Cat, except that the ligaments suspending them to the spine are very 

 short, and they are contained in a fold of peritoneum. 



Develoi'ment. 



The development of the ovaria and the ova is very interesting. In 

 the Mare, the ovaria of the fa'tus are, when compared with the uterus, 

 of an immense size, and at six months are almost as large as in the 

 adult. In aged animals they become atrophied, and it is not unusual 

 in old Mares to find either one or both in an unhealthy condition. Not 

 infrequently they are hypertrophied, and their fibrous envelope and 

 stroma are much thickened. Sometimes the vesicles are greatly en- 

 larged, and converted into cysts which contain a limpid, sanguinolent, 

 or purulent fluid, secreted from their walls. Flandrin cites the case of 

 a ^lare, one of whose ovaria weighed 26k pounds, and measured 

 14i inches in its long, and 12 inches in its short diameter. The 

 texture of the ovaries is also liable to various abnormal alterations. 



The Graafian vesicles are present in the ovary of the fcetus, but they 

 do not attain their full development mitil puberty ; neither are they all 

 present at birth, but are continually being developed beneath the tunica 

 albuginea. The first-formed elements in the fcttal ovary are cells and 

 cell-nuclei ; these next appear in somewhat circular groups, which are 

 more opaque than the other parts of the regularly uniform mass (Fig. 

 31, A). A kind of film soon condenses round these groups (B), and upon 

 the inner surface of this there is fixed an epithelial precipitate from the 

 fluid and granules of the interspaces of the contained primary cells. 

 Within the ovisac thus formed, a large nucleate cell becomes visible : 

 this is the commencement of the ovum (C, (j). As this expands, the 

 proportion of fluid to the formed particles increases, and the latter 



