MaleMusFIG 29: Connection of the protractor muscles to the spicules.

A. Low-power TEM featuring the location of the spicules within the spicule protractor muscle, transverse section. (PAG) Pre-anal ganglion; (v/dsrL/R) ventral and dorsal spicule retractors, (v/dspL) ventral and dorsal spicule protractors. (Image source: N2Y [MRC] 597-5.)
B. TEM of boxed area in 29A showing close up of the hemidesmosomes (red arrows) that interconnect muscle, basal lamina, proctodeum and spicule. (Bl) basal lamina. (Image source: N2Y [MRC] 517-4.)
C. TEM of boxed area in 29B showing close up of the attachment plaques (yellow arrows) that link spicule muscles to each other, dorsal protractors to ventral protractors and dorsal protractors to the anal depressor. (Image source: N2Y [MRC] 517-4.)