Ceratobranchia obtusirostris (Fig. 7 A-D)

In the spermatozoa of Ceratobranchia obtusirostris the nucleus measures 1.3 µ m in the longitudinal axis and 1.1 µ m in the transverse axis. The surrounding strip of cytoplasm has no organelles (Fig. 7A). Nuclear rotation toward the flagellar axis was about 70 degrees (Fig. 7 A-B). The midpiece has a conical shape, measures about 0.6 µ m in length, and contains some slightly elongate mitochondria (Fig. 7 A-D). Information on the endomembrane system is not available, since the specimens of C. obtusirostris have been obtained from ichthyological collections and the gonads were not appropriately preserved for ultrastructural analysis.