Ultrastructure of the Ceca of the Digenetic Trematodes Gorgodera amplicava and Haematoloechus medioplexus

Abstract

Electron microscopy of the ceca of the digenetic trematodes C. amplicava and H. medioplexus has revealed morphological specializations for both absorption and secretion. The cytoplasm lining the cecal lumen of both species contains an extensive granular endoplasmic reticulum, prominent Golgi complexes, dense membrane-bound granules, and numerous mitochondria. The lumenal surface is extended as digitiform microvilli in G. amplicava and as ridgelike folds in H. medioplexus. The basal plasmalemmae are highly infolded and incompletely partition the cecal lining. Lateral cell membranes are absent in the enteric cytoplasm of G. amplicava. In H. medioplexus, however, lateral membranous boundaries are present and joined near the apical pole of adjacent cells by septate desmosomes.