INTERNAL ORGANS OF GENERA T/ON 47 



to the exterior boundary of the aperture opposite the ovarium, while the 

 tube itself, long and fine, passes in a wavy course round the anterior 

 aspect of the latter to the uterus. The length of the tube is from two 

 and a half to three and a half inches. 



SECTION IV. THE OVARIES. 



The ovaries (testes muiiebres), the essential organs of generation in the 

 female, and analogous to the testes of the male, are two ovoid or elon- 

 gate reniform bodies, smaller than the latter, but of the same shape, and 

 situated in the abdominal cavity. They are loosely suspended in the 

 sub-lumbar region, behind the Fallopian tubes and the kidneys, among 

 the convolutions of the intestines ; though sometimes their position is 

 altered. In four instances in the Pig they have been found in the peri- 

 neal region, occupying small cavities analogous to the scrotum of the 

 male.* Smooth externally, each ovary shows in the middle of its upper 

 portion a more or less oblique, but deep fissure, resembling the hilus of 

 the kidney, and which gives attachment to the pavilion of the Fallopian 

 tube. Each ovary is suspended at the anterior border of the broad liga- 

 ment, and is also sustained in situ by the vessels passing to and from it, 

 as well as by a small cord of non-striated muscular fibres called the iiga- 

 mentum ovarii, which connects it with the uterus. 



The structure of the ovary comprises a serous and fibrous membrane, 

 the proper tissue of the ovary, and the Graafia7i vesicles embedded in it. 

 The serous membrane is continuous with the broad ligaments — is, in fact, 

 a peritoneal tunic, which entirely envelops it, adhering closely to the 

 covering beneath. This is the tunica albuginea : a dense resisting mem- 

 brane similar to the structure enveloping the testicle, and sending lamel- 

 lar prolongations into the substance of the ovary. 



T\\e. proper tissue or stroma of the ovary is solid and hard, and has a 

 speckled-grey tint. It is divided into two layers, which are distinct in 

 appearance and structure. The medullary layer is nearest the hilus, and 

 is somewhat red and spongy • it is formed by the intercrossing of con- 

 nective tissue, non-striated muscular fibres, and by a large number of 

 vessels which radiate from the centre towards the periphery of the organ 

 and nerves. The cortical layer has for its basis connective tissue ; it is 

 not very vascular, but it contains in its substance the Graafian vesicles or 

 follicles, and for this reason is named the ovigenic layer. 



These Graafian vesicles are generally in various stages of development ; 

 the smallest are situated beneath the tunica albuginea, and they descend 

 towards the deeper layer, increasing in volume as they do so. When they 

 have reached their period of full growth, they are filled with a transparent 

 citron-colored fluid, and the ovigenic layer being incapable of containing 

 them, they form a more or less considerable prominence on the surface of 

 the ovary. A Graafian vesicle, when perfect, is composed of an envelope 

 and its contents. The envelope com^xxso^s two tunics — a fibrous membrane 

 (tunic of the ovisac), which is confounded externally with the stroma of the 

 ovary, and internally is rich in blood-vessels ; an inner {ovisac), formed 

 by a smooth membrane which derives its blood-vessels from the latter ; 



* A remarkable, if not unique, case of displacement of the ovaries is recorded by M. Dupont, in the 

 Journal des Veterinaires du Midi for 1869. In four female pigs, fifteen days old. beneath the vulva 

 were observed two protuberances exactly like the testicles of the male, and which, on examination after 

 death, proved to be the ovaries. The other organs of generation were normal- The same Sow which 

 produced them, had, in a previous litter, brought forth two females with the ovaries similarly misplaced. 



