A group of animal cells in which cytoplasmic continuity is maintained. For example, the cells of striated muscle form a syncytium. In some syncytia the cells remain discrete but are joined together by cytoplasmic bridges. For example, developing male germ cells in the testes of mammals are linked throughout the process of differentiation until an individual sperm is released into the lumen of the seminiferous tubule (see spermatogenesis). Compare plasmodium.