On the reproduction of brazilian fishes .Ix. Spermatogenesis of the surubim pseudoplatystoma corruscans agassiz 1829 ( pisces , pimelodidae) - Lopes, R A; Leme dos Santos, H S; Paula-Lopes, O V; Nuti Sobrinho, A; Paula, C V (Ars Veterinaria, 1987)