Studies On Histology Of Reproductive System And Cell Biology On Spermatogenesis And Oogenesis Of Octopus Variabilis

Octopus variabilis is a commercially important marine cephalopoda in China. The structure of reproductive system and gametogenesis are investigated for further study on its reproductive biology,using the techniques of anatomy, tissue section,transmission electronic microscopy, scanning electronic microscopy.The main results are as follow:1.The histological study of reproduuctive systemThe Octopus variabilis is dioecious.The reproductive system located at the end of coelom.The male reproductive system is composed of spermary,spermaduct,vesicular seminalis(including the fornt segment,the middle segment and the end segment) , prostate gland, spermatophore sac and penis. The wall of the vesicular seminalis is very complex, with tonguelet fingering out into the cyst cavity.There are a lot of glandular cells in the wall of vesicular seminalis and tonguelet.The female reproductive system is composed of ovary, oviduct and uterine gland.Oviduct is long, openning at the funnel mouth. The structure of uterine gland is complicated,with a thelycum in it.2.spermatogenesis and the testis developmentDetailed observations and descriptions of morphological and structural changes of cells as well as transformation of cell organells were made submicroscopically from spermatogonia to spermatozoa. The development of spermatogenesis is divided into five phages:spermatogonia, primary spermatocytes,secondary spermatocytes, spermatid and sperm.According to the morphological and structural change of nucleus as well as the formation of acrosome and flagellum,the phage of spermatid is divided into five phages.According to the development of male germ cells and the ratio of different male germ cells in the spermary,we divide the course of testis development into five stages.â… : The spermary can't be seen with visual inspection.Dominated male germ cells are spermatogonium.â…¡: The main cells are primary spermatocytes and secondary sperm- atocytes.There are still a small quantity of spermatogonia.â…¢: Dominated male germ cells are secondary spermatocytes and spermatid.Mature sperm has been formed.â…£: There are a large number of sperms in the autumn testis.â…¤: the degenerate testis. 3.oogenesis and the ovarian developmentAccording to the histology research, the process of oogenesis may be divided into four stages:â‘ multiplication of oogonium;â‘¡growth of oocytes;â‘¢autumn of oocytes;â‘£the stage of resorbing oocytes.According to the relationship between oocyte and follicle cells, the third stage of oogenesis is divided into four phages.On the basis of development of ovary and the quantity ratio of different oocytes, the course of ovarian development is divided into six stages.4.the structrue of spermatophoreSpermatophore is stored in the spermatophore sac,and is the deposited storehouse of sperm of Octopus variabilis.From the appearance,the spermatophore can be divided into two parts.One part is the powerplant in the head of the spermatophore, which is transparent. The other part where the sperms store is milky.Spermatophore's internal structure is very complicated and the powerplant in the head plays a very important role in sperm transfer- rence.When mating,the male octopus will transport its spermatophore to the opening of oviduct using its hectocotylus.Then,the powerplant starts,pulling the sperms into the thelycum of uterine gland through the long oviduct. A few months later,the fertilization will be completed when spawning.The complex mechanism resolves the problem that the oviduct is too long for sperm entering the thelycum,also resolves the problem that male and female octopus get sexually mature inconsistently.