This article examines isothermic surfaces smoothly immersed in Mobius space
. It finds explicit examples of non-special, non-canal isothermic tori with
spherical lines of curvature in two systems by analyzing Darboux transform
s of Dupin tori. In addition, it characterizes the property of spherical li
nes of curvature in terms of differential equations on the Calapso potentia
l of the isothermic immersion, and investigates the effect of classical tra
nsformations on this property.