A detailed morphological study of the littorinid Littorina flava (King & Broderip), from Venezuelan and Brazilian coasts, is given and commented. a considerable degree of shell characters variation was found, mainly in color and sculpture. The pallial cavity presents normal fashion of mesogastropods, without any detectable morphological modification for the long air-exposure. The digestive system present odontophore muscles very similar to those of the cerithioideans and hydrobioideans; the radula, however, is enormously long; the stomach lacks differentiate style sac. The penis is characteristic in lacking annex glands. The pallial oviduct has no jelly gland, and has a well developed bursa copulatrix and vaginal tube.
Mollusca; Littorina flava; morphology; systematics; Brazil