atypic

Another variety, found chiefly among the lowest grades, might well be termed “atypic.”

Atypic -ical: off type; not of the usual form.

Among the older naturalists, such as Pliny and Aristotle, and even in the older historians, whose scope included natural as well as civil and political history, the atypic and bizarre, and especially the aberrations of form or function of the generative organs, caught the eye most quickly.

We have to consider the general problem; to study the conditions of all typical as well as of atypic forms, in other words, to found a physiology of form.