| Cipangopaludina chinensis is a normal kind of freshwater gastropod and has high economic values because it can be food for people, which not only tastes well but also is high nutrient, and it can be the bait for some carnivorous fish and some omnivorous fish such as Mylopharyngodon piceus and Cyprinus carpio.Many foreign scholars and a few Chinese scholars have studied the ultrastructure of the mature sperm and Spermatogenesis of gastropod; however, nobody has studied the ultrastructure of the mature sperm and Spermatogenesis of Cipangopaludina chinensis. In view of its high economic values, the author studied the ultrastructure of the mature sperm and Spermatogenesis of Cipangopaludina chinensis in order to supply the basic materials of the reproductive biology of Cipangopaludina chinensis.In this paper, the methods that the author used are as follows:Light microscopy:The testis was fixed in Bouin's fluid, dehydrated in an ethyl alcohol series, embedded in paraffin, sectioned at 6 u m and stained with Hematoxylin and Eosin, then observed with Olympus microscopy and photographed.Scanning electron microscopy:After fixed in 2.5% glutaraldehyde made up in 0.1 M phosphate buffer (pH 7.2), the tissue of testis was post-fixed in 1.0% OsO4, dehydrated in a progressive ethanol solution, dried and sputter-coated with gold, then observed with KYKY-1000B microscopy and photographed.Transmission electron microscopy:The testis was cut into fragments (1mm X 1mm X 1mm), fixed in 2.5% glutaraldehyde made up in 0.1 M phosphate buffer (pH 7.2), postfixed in 1.0% OsO4, dehydrated in a progressive ethanol and acetone solution, embedded in Epon812, sectioned with LKB ultramicrotome, and stained with urangl acetate followed by lead citrate, then observed with H-600 microscopy and photographed.Cytochemical methods:The testis was fixed in cold acetone, embedded in paraffin, sectioned at 6 u m, observed with Olympus BH-2 microscopy and DNA was showed with Feulgen, glycogen was showed with PAS.In present study, we found that Cipangopaludina chinensis has two kinds of sperm, one is the viable typical sperm, and the other is the unviable atypical sperm. Sperm bimorphism is a common phenomenon through the animal kingdom, especially ingastropod, such as most of mesogastropod and neogastropod and some of archeogastropod. Typical sperm, which has normal amounts of chromatin, can take part in fertilization; however, atypical sperm, which has abnormal amounts of chromatin, or has no chromatin, can't take part in fertilization, but has nutritional function.The typical sperm of Cipangopaludina chinensis, having spiral nucleus, long and spiral mitochondrion and a large number of glycogen granules, belongs to the modified sperm.According to the changes of the structure of chromatin and the morphology of cell, the process of the typical spermatogenesis of Cipangopaludina chinensis can be divided into five stages: spermatogonium, primary spermatocyte, secondary spermatocyte, spermatid and mature sperm. The spermatogonium contains obvious nucleolus and abnormally condensing chromatin. In the primary spermatocyte, nucleus begins to have two layers of membrane; mitochondria gradually gather at the posterior of cell and ergastoplasm secrets a large number of vesicles. In the secondary spermatocyte, some mitochondria begin to fuse. The spermatid changes greatly, including that chromatin gradually condenses from exterior and anterior to interior and posterior, and has a homogeneous appearance after granular appearence and fibrillous appearence; the posterior of the nuclear membrane thickens and invaginates into a vessa, followed with centriole transporting into the vessa and producing axis. Following with the condensing of chromatin, nucleus gradually elongates and spires. A large number of vesicles turn into glycogen granules behind mitochondria.The mature typical sperm of Cipangopaludina chinensis, having monoflagella, consists of a spiral head with only one spiral buddle conformed of nucleus, a spiral middl...
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