Sexual system - a set of organs that ensure the production, development and excretion of sexual products (sperm and eggs), and in viviparous species - live calves. Sexual glands (gonads} - testes in males and ovaries in females - ribbon-shaped or sac-like formations located in the body cavity above the intestine, under the swim bladder. In piscivorous sex gland is unpaired, there are no ducts. In cartilaginous and bipedal sexual system is connected with the excretory system. Müller's ducts of these fishes are modified into oviducts, and Wolff's ducts either perform the function of ureters only (females), or serve as seminal ducts (males). In bony fishes, sexual products are excreted through independent sexual ducts opening into the urogenital or genital opening.