Mounting medium used for the microslide preparation of feathers, this technique has been developed by Dr. R. Laybourne. Flo-Texx (methacrylate copolymer 37.5, butyl benzyl phthalate 2.3, 2,6-di-tert-butyl-p-cresol 0.3 percent by volume) has the same refractive index as water. Flo-Texx is available from Lerner Laboratories, 171 Industry Drive, Pittsburgh, PA 15275 USA (Laybourne and Dove, 1994).