Something very similar to Faust's cell presented itself to Jehan's view, when he ventured his head through the half- open door. It also was a gloomy and sparsely lighted retreat. There also stood a large arm-chair and a large table, compasses, alembics, skeletons of animals suspended from the ceiling, a globe rolling on the floor, hippocephali mingled promiscuously with drinking cups

I could not find out what "hippocephali" referred to. Reminds me of the HH:HA dissociation, which decrees that the world shall have an excess of horses' asses over horses'
heads.