Complex sentence: Apertures vary from round to T-shaped, with a long, narrow hyponomic sinus Siphuncles are commonly central or subcentral with generally broad, expanded, segments and usually thin connecting rings.
Split into simpler sentences: Apertures vary from round to T-shaped, with a long, narrow hyponomic sinus. The siphuncles are commonly central or subcentral with generally broad, expanded, segments and usually thin connecting rings.