Here is a inflated head of Dalmanitina socialis from Beroun. Both eyes are showing the lens structures of the compound eye. The right cheek edge runs out of the matrix.
Location:
Ded Hill, Beroun, Barrandian area, Czech Republic
Size trilobite:
about 39 mm wide
Age:
Middle Ordovician, Llandeilo, Letná Formation (About 464 mill. Years old)