This is a seal from the book "Lesser Key of Solomon". According this text, the spirit Dantalion, is described thus
"The Seventy-first Spirit is Dantalion.
He is a Duke Great and Mighty, appearing in
the Form of a Man with many Countenances, all Men’s
and Women’s Faces; and he hath a Book in his right
hand. His Office is to teach all Arts and Sciences unto
any ; and to declare the Secret Counsel of any one ; for
he knoweth the Thoughts of all Men and Women, and
can change them at his Will. He can cause Love, and
show the Similitude of any person, and show the same
by a Vision, let them be in what part of the World they
Will. He governeth 36 Legions of Spirits; and this is
his Seal, which wear thou, etc"