The type of Phyllaplysia, Ph. lafonti (P. FISCHER, 1870, p. 3—4) had been introduced with 40 specimens (id. 1872, p. 299). But FISCHER has found this rich material only once, and also the slugs of the other species of the genus have rarely been found (CUÉNOT, 1927, p. 259). ENGEL (1936, p. 210) says: “Ces animaux sont si rares et si mal connus que la connaissance du genre a forcement un caractere provisoire”. Phyllaplysia engeli Marcus (1955, p. 105), however, is frequent among algae, Padina and others, which grow on stones in the upper littoral of the coast of S. Paulo, and so we can complete our first description. The cutaneous villi are sometimes arborescent, and even the rhinophores may bear papillae. The anterior border of the foot is occasionally bilabiate. Also in these cases it is connected with the lateral margins of the body, so that the difference against Petalifera with free anterior border of the foot (ENGEL, 1936, p. 200; ENGEL & HUMMELINCK, 1936, p. 48) continues to be valid.