He does not merely appropriate their external form in some way.
Species is an older English word meaning 'external form or appearance'.
The external form is the same; the internal structure likewise.
Women can wear an external form in their bra if they choose.
The external form of the polyp varies greatly in different cases.
Thus a word usually has three aspects: an external form, a meaning, and an internal form.
There are two forms of mediation, external and internal.
In our universe and others, the books suggest that dæmons are integrated with the person, without any external or physical form.
Mirror of matter - The external form of an inner concept.