Transverse sections of late stage spermatids in (a) the emu, (b) ostrich and (c) rhea. Note the prominent longitudinal manchette microtubules (stars), the finger-like projections (encircled) closely associated with the outer nuclear membrane (black arrows) and the condensed chromatin of the nucleus (N). Individual manchette microtubules are closely aligned with, but not attached to, the finger-like projections. In some regions the projections appear as a fuzzy moderately electron-dense layer due to the plane of section (block arrows). The perforatorium typical of ostrich and rhea spermatids is visible within the nucleus (white arrows). Bar = 0.5 μm.
du Plessis and Soley BMC Evolutionary Biology 2013 13:104 doi:10.1186/1471-2148-13-104