Hemibrycon surinamensis (Fig. 10 A-F)

In the spermatozoon of Hemibrycon surinamensis the ovoid nucleus measures 1.52 µ m in the longitudinal axis and 1.2 µ m in the transverse axis. The surrounding strip of cytoplasm has no organelles (Fig. 10A). Nuclear rotation toward the flagellar axis was about 95 degrees (Fig.10A).The midpiece has a conical shape, measures about 0.9 µ m in length and contains some slightly elongatemitochondria(Fig.10A).Apossibleendomembranesystem seems to be composed of a clump of small vesicles (Fig.10 B-F).