ABSTRACT
Based on the micropuncture studies of Jones et a!. (1984), it is concluded that luminal fluids of efferent ducts and the epididymis when
382 Reproductive Biology and Phylogeny of Chondrichthyes
compared to blood plasma show higher levels of sodium, potassium, protein and have a greater osmolarity. Spermatocrit samples from the epididymis and ductus deferens reveal that virtually all fluid is resorbed. The per cent sperm motility increases when testicular (9%) samples are compared with epididymal samples (96'/'o) despite any ultrastructural change. These data suggest that the epididymis and Leydig gland secretions play important roles in ion and water transport, protein secretion and maturation of spermatozoa. ln He/erodontus, only the seminal vesicle has a muscular tunic, all other segments of the duct system convey sperm via ciliary activity (Jones and Lin 1993) and pressure exerted by secretory activity in the more proximal ducts.
