Unidirectional solidification of very thin specimens of PbSn has been investigated by Racek; thin In 2Bi In lamellar cutectic ribbons are produced by the same experimental procedure. The lamellar structure of these specimens is perfect in areas of about 0.5–1 mm 2. The relationship between the interlamellar spacing λ and the growth rate ν has been determined: λ 2,3 ν = 3.47 × 10 −18 MKS. The orientation relationship is: growth direction ‖ ∥101∥ In ‖ ∥010∥ In 2Bi ; lamellar interface ‖ (12 1 ) In ‖ ( 1 02) In 2Bi . The PbSn and InIn 2Bi systems are compared. The results are explained by a large anisotropy and a slow growth kinetic of the In 2Bi phase. Thermal vibrations of low frequencies of In chains parallel to the c-axis are shown in the In 2Bi eutectic phase.