Not only with iron pins, but also with melted wax, are animals secured to the plate of earth. Wash them first in clear water, after they have died in the mixture of vinegar and urine. And with a sponge clean off their mouth, eyes and head of the froth coming out, because the sand would never set well there and would become lumpy.
at left top margin of folio 165v
If you want to keep their mouths open, insert a little bit of harpsichord string, which will not take up much space.