Observations on the structure and histology of the gut in some digenetic trematodes

Summary

In a study on 20 species of digenetic trematodes belonging to 13 families we could recognise six basic histological conditions (1). Gastrodermis of uniform height without any brush border (2). Gastrodermis of uniform height but with microvilli (3). Gastrodermis which presents pyramidal ridges projecting into the lumen in the absence of food but more or less of uniform height in the presence of food. In both the stages characteristic microvilli make their appearance (4). Gastrodermis presents two different stages—when the lumen is free of food the cells are club-shaped or columnar or cylindrical and when food is present it shrinks to flat or cuboidal gastrodermis (5). Two stages of gastrodermis as mentioned in the previous condition but the brush border makes its appearance only in the flat cell condition (6). Two stages of gastrodermis—in both the stages the brush border is present. Thus six different gastrodermal organisations could be made out. The histological structure seems to be independant from the family to which the parasite belongs or its habitat or food habits.