• T.S passing through pharynx of Dugesia showing its triploblastic and acoelomate nature.

• Body wall layers are Epidermis, Muscle layers and Mesenchyma.

• Epidermis is syncitial, ciliated, single layer of columnar cells with rounded nuclei, epidermal cells containing rod – shaped rhabdites.

• Below epidermis is muscle layer, separated by basement membrane.

• Muscle layer consist of outer circular, middle diagonal and inner longitudinal fibres.

• Mesenchyma is found just below muscle layers, it contains mucous glands, rhabdites, forming gland and other organs.

• Pharynx in T.S shows pharyngeal sheath, pharyngeal chamber, epithelial layer, circular muscles, longitudinal muscles and glandular layer.