The deference in nucleus form depended on developmental and physiological activities. In early spermatogenesis, nuclear structure of three species is very similar. The shape of spermatocytes changed from round or ellipse to polygon. Chromatins concentrated gradually and dispersed in karyotin or inner karothece in spermatocytes stage. Nucleolus shrank, dispersed, and finally disappeared. In spermatocytes stage, nuclei membrane vesiculation was significant and the number of nucleopore complexes increased, which are good for transporting RNA and ribosomes into cytoplasm to ensure material supply for synthesizing proteins.

Some similar features were shown in ultrastructure of organelles of S. marmoratus, S. macrocephalus and R. sarba (Forskai) during primary spermatogenesis. The mitochondria with developed ridges dispersed sharply in spermatocytes stage, and they were small and the cristae were undeveloped in spermatogonia stage. The lysosomes were in shape of vesicle in high electron-density. Chromatoid bodies linking mitochondrins were observed only in the cytoplasm of S. marmoratus, and no Golgi body was found in cytoplasm of S. marmoratus. Typical Golgi body and myelinoid body were observed in cytoplasm of S. macrocephalus.