الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
The present investigation was carried out on 150 balady rabbit embryos and fetuses ranging from 9 days postconception up to full term. The crown vertebral rump length (C.V.R.L) was measured.
The gonads of rabbit fetuses aged from 23 days up to full term were photographed in situ by using a codak digital camera for gross morphological studies.
The whole embryos and fetuses, the caudal halves and the gonads from 9 days up to full term were prepared to obtain 4-6 um thick paraffin sections and stained by different stains to be studied by a light microscope.
The present study revealed that the prenatal development of the gonads of the balady rabbit embryos and fetuses could be divided into three main stages:
I- The indifferent gonad.
II- The development of the fetal testes.
III- The development of the fetal ovaries.
I- The indifferent stage.
The gonadal ridges were detected at the 12th day postconception as a cellular thickening covered by coelomic epithelium on either sides of the dorsal mesentery and attached to the developing pronephros. As the development progressed the gonadal ridge increased in size and cellular constituents and became housing blood vessels and germ cells.
II- The development of the fetal testes.
A- Gross morphological studies:
The gonads could be identified grossly into testes at the 24th day postconception at which the shape and position were identified.
B- Histological studies:
The indifferent gonad of rabbit started their differentiation into fetal testes at the 18th day postconception at which the primitive incomplete tunica albuginea and the testicular cords appeared. The later consisted mainly of gonocytes and supporting cells and they remained solid without lumen along the prenatal life. The primitive rete cords appeared at the 24th day postconception.
III- The development of the fetal ovaries.
A- Gross morphological studies:
The gonads could be identified grossly into ovaries at the 24th day postconception in which the shape and position were identified.
B- Histological studies:
The ovarian differentiation of rabbit occurs at the 19th days postconception at which the ovarian cortex and medulla were recognized. The oogonia and stromal cells formed oogonial nests within the ovarian cortex at the 24th day postconception. The primitive tunica albuginea ovarii could be recognized as late as the 28th day postconception. Neither primordial follicle nor interstitial cells occurred throughout the fetal rabbit life.
- The results obtained were illustrated in seventy four photographs of rabbit
embryos and fetuses.
- The current results were discussed with those given by previous authors in different laboratory animals as well as in goat, sheep and dogs.