Abstract
The angular distribution of directional change of mouse fibroblast 3T3 cells which followed guiding lines on a substrate and left the guidance at various angles shows a peculiar preference for angles between 30.degree. and 60.degree.. Regarding the phenomenon of cellular guidance itself, 3T3 cells faced with a choice between guiding lines toward difterent directions seem to explore various options before following one. The outcome of a probing action and not substrate properties alone may explain the guidance behavior of 3T3 cells.