SummaryThe intestine of Mugilidae (Pisces; Teleostei) at different growth stages.I. Morphological and histological aspectsA morphological and histological study of the intestine of Mugilidae (Mugil cephalus, Liza aurata, Liza ramadaandLiza saliens) has been carried out from the larval to the adult stages. The allometric relationship between length of intestine and standard length of fish are represented by regression lines correlated with species and kind of diet. S.E.M. observations on the intestinal mucosa surface show finger‐like villi, as in Mammals. Histologically, the mucosa structure appears similar to that in others Teleosteans. The gobblet cells are scarce in the larval stages but very numerous in the juvenile stages; furthermore, they are more abundant in the posterior than the anterior part of the intestine (respectively 25 and 10%). Change in the feeding habits observed in young stages has no effect on the features of the intestine but notably increases its relative lengt