The spermatozoon of Silurus soldatovi consists of head , middle piece and tail .The head is like a globe or an ellipsoid .There is no acrosome at the anterior end of the nuclears , whereas there is an implatation fossa at the posterior end of the nuclears , within which the chromatin is dense and nuclear vacuole(NV)is existent.The middle piece consists of the centrioles and the sleeve .Two single hemi-global centrioles are opposite to each other , thus constituting the proximal centriole , an empty globe , which is nucleus-dense .The distal centriole is like a bell , with its top connecting to the proximal centriole and with the entrance of its bottom connecting to the axoneme of the sperm tail .The sleeve , which is rich in mitochondria and vesicles , is connected to the posterior end of the nucleus .The main structure of the tail is axoneme ,which is the structure of a typical “9 +2” .There are no vesicles nor other cell organelles in the tail .The outer surface of the tail is quite smooth without fin-like structure .