Figure 3 in Sperm ultrastructure in two species of Gyraulus (Gastropoda: Pulmonata: Planorbidae)

Figure 3. Longitudinal (LS) and transverse (TS) transmission electron micrograph sections of spermatozoa of Gyraulus (Armiger) crista. (a, b) LS, head of a spermatozoon at the final stage of maturation. (c) LS, internal structure of the acrosomal complex. (d) TS, middle portion of the nucleus. (e) TS, basal portion of the nucleus with trapezoid coarse fibres and a single glycogen mass surrounded by a thin band of mitochondrial derivative. (f) TS, neck region with triangular coarse fibres and four glycogen helices enclosed within the mitochondrial derivative. (g) LS, middle portion of the midpiece with three glycogen helices, mitochondrial derivative and axoneme. (h) TS, middle portion of the midpiece with two glycogen helices, mitochondrial derivative and axoneme. (i) TS, posterior portion of the midpiece with a single glycogen helix. (j) TS, portion of the midpiece without glycogen helices. (k, l) LS, annulus region showing a ring at the tip of the mitochondrial derivative (black arrows) and a cylinder at the anterior end of the glycogen piece (white arrows). (m) TS, glycogen region with the axoneme. (n) TS, axoneme in the tail region with a complete 9 + 2