STUDIES ON ULTRASTRUCTURE OF THE SPERM OF FRESHWATER MUSSEL,CRISTARIA PLICATA

The morphology and ultrastructure of the sperm of Cristaria plicata were studied with electron microscope. The results show that the sperm is 40-43μm long and consists of the head,the middle piece and the flagellum. The 1.5×2.6μm sperm head is bullet shaped and contains a nucleus which is condensed and delimited by a nuclear membrane. The middle piece(0.6μm long)composes of five spherical mitochondria. A proximal centriole is locatesd in a fossa in the nucleus base and connects to a distal centriole by a dense amorphous matrix. The distal centriole is located to the flagellar collar. The flagellum is 37-40μm long. A very reduced acrosome is only composed of several acrosomal vesicles.