AbstractThe regenerative ability of limb stumps bearing partial circumferences of flank skin was tested in the newt,Notophthalmus viridescens. Skin dorsal to the lateral line of the flank was removed and used to replace 1/4, 1/2, or 3/4 of the skin of the upper forelimb. Grafts were placed at anterior, posterior, dorsal, or ventral positions relative to the axes of the limb. After 30 days of graft healing the limbs were amputated through the grafts and were permitted to regenerate for 60 days. Limb stumps bearing 1/4 circumference of flank skin regenerated complete limbs in 85% of the experimental cases. After 1/2 circumference of limb skin was replaced, 57% regenerated complete limbs. When 3/4 of the limb skin was replaced by flank skin, 29% regenerated complete limbs. Only 2% of experimental limbs bearing a full circumference of flank skin regenerated complete limbs in an earlier study [Tank, P.W. (1984) J. Exp. Zool., 229:143–153]. The greatest effect on pattern formation was observed when flank skin grafts were placed at the ventral position of the limb stump regardless of graft size. These results are discussed in light of the idea that short‐range cellular interactions between limb cells are essential for pattern formation during limb regenerat