The ultrastructural characteristics of euspermatogenesis and mature euspermatozoa of Cerithidea cingulata are described. Euspermatogonia possesses a large round concentric nucleus with one or two nucleoli. The spermatocyte is characterized by the abundant cytoplasmic organelles and eccentric nucleus with chromatin distributed throughout as small granules. https://www.espumasyterciopelo.com/product-category/cards/