They did sit in my lap for a few hours
Neale Monks;141053 said:I can't speak for regular ammonites, but at least some heteromorph ammonites show distinct apertural modifications depending on their gender. Among Lechites for example (if I remember correctly) the macroconchs have a curved aperture, so that the end effectively curls over by almost 90 degrees; by contrast the microconchs this is not the case, but the aperture is fluted, a bit like a complex spout. I think Sciponoceras shows a similar thing.
Cheers, Neale