The ontogeny of the alimentary tract of coregonid larvae: normal development

The development of the alimentary tract in larvae of Coregonus fera fed with Anemia nauplii has been examined histologically from the 4th to the 24th day after hatching. Buccal cavity and oesophagus are nearly completely developed before the start of feeding. The stomach exists only as an ‘anlage’, but starts to store food during the study period. The intestinal absorptive cells are stuffed with fat vacuoles between the 7th and 13th day after the start of feeding. During this time the rectal absorptive cells contain one large supranuclear body consisting of protein. The occurrence of large vacuoles in the intestinal and rectal absorptive cells may be caused by a partial non‐functioning of the larval digestion; after two weeks of feeding this restriction seems to be overcome.