Dear dxb: I couldn't find a picture of a cotylosaur, but the site said it was also called "Captorhynic". I wonder if that meant it had a horn on its nose, which might meat that a cotyle was a cup made from a horn.

P.S. I just remembered that there is a term in obstetrics
for a condition in which the placenta is not a single unit, but has accessory structures called cotyledons, which if retained can cause postpartum problems. I have seen cotyledons, but never complications from them.