We have been investigating the development of the toe-pads of the frog Phyllomedusa irinhuiis. Several families of frog appear to have evolved rather similar digits with expanded terminal pads where ventral surfaces are specialised for adhesion. Although toe-pad structure has been extensively studied, development - which may gives clues to evolution - has not.

Adult and eggs of P. Iriniialis were collected from Trinidad, West Indies. Tadpoles were grown in our aquarium in Glasgow. We fixed front and hind digits of tadpoles at Gosner (1960) stages 37-42, froglets at stage 43-46, and adults. Pads were then processed for SEM.

Adult toe pads have a specialised epidermis with a surface layer of hexagonallyshaped cells, separated by deep clefts into which mucus glands open. Each pad is separated from the rest of the digit by a circumferal groove (Fig. 1).