Ultrastructure of the epimastigotes of the fish trypanosome Trypanosoma cobitis Mitrophanow 1883, in the crop of the leech vector, Hemiclepsis marginata.

The ultrastructure of the epimastigote of Trypanosoma cobitis in the crop of the leech vector Hemiclepsis marginata is described. Microorganisms, closely resembling endosymbiotic bacteria, seen in monoxenous trypanosomatids, were present in the cytoplasm. Also, within the cytoplasm were ribosomes, sparse endoplasmic reticulum, a Golgi apparatus, and a wide variety of other inclusions, in particular multivesiculate bodies which appeared to contain waste material. The well-developed branched mitrochondrion had platelike cristae and an expansion near the nucleus which contained the kinetoplast DNA. A cytostomal opening situated near the flagellar pocket leads to a cytopharynx surrounded by five microtubules.