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Advancement of instrumentation in the field of biology has facilitated the use of electron microscopy for ultrastructural studies of cestodes. However, they have some limitations. Not much has been done in the recent years to explore simple techniques for preliminary investigations of cestode reproductive systems. Application of histochemical techniques have mostly been limited to identify the localized biochemical molecules in cestode tissues despite their potentiality to decipher structural details. Earlier studies have heavily relied on Periodic Acid-Schiff (PAS) reaction and its variants to document the cestode architecture as a secondary data where the primary aim was to study the sites of carbohydrate deposition. Most of the works did not provide a detailed account of the reproductive structures and/or the egg forming apparatus along the cestode strobila. In this respect, it may be said that the potentialities of the histochemical techniques in this field have been poorly explored.  Mercury Bromophenol Blue (MBPB) technique is one of them that has not found much importance in earlier studies as far as elaborating the cestode architecture is concerned. As such, the usefulness of MBPB technique (Bonhag, 1955) to study the development of reproductive organs of cestodes has been explored in this work using Cotugnia cuneata as the model cestode. The stained tissue sections of the cestode strobila were studied under a light microscope at different magnifications and the development of the reproductive organs were recorded separately for anterior, middle and posterior regions of the specimen. The technique elaborated the development of the reproductive structures including the development and regression of the egg-forming apparatus. The female reproductive structures could be studied better. A few reproductive structures (of both sexes) were, however, not decipherable. Thus, despite minor drawbacks, the technique may be used for preliminary studies of the cestode reproductive structures especially while documenting new species.

Cestode, Cotugnia cuneata, Histochemistry, Mercury Bromophenol Blue technique, Reproductive structures, Egg-forming apparatus

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