Anallagmatic
An`al`lag`mat´ic
a. 1. (Math.) Not changed in form by inversion.
Anallagmatic curves
a class of curves of the fourth degree which have certain peculiar relations to circles; - sometimes called bicircular quartics.
Anallagmatic surfaces
a certain class of surfaces of the fourth degree.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.