The ultrastructure of the epithelium of the ducts of the Harderian and lacrimal glands of the turkey, fowl and duck.

The ultrastructure of the epithelium in the Harderian and lacrimal gland ducts of the turkey, fowl and duck has been investigated. The findings establish that the ducts are fundamentally similar in morphology, although species differences occur. The duct epithelia are composed of cuboidal, columnar or pseudostratisfied columnar cells with many secretory vesicles as well as goblet cells. PAS-positive fibrillary rods and crystalline inclusions occupied the cisternae of the rough endoplasmic reticulum of the epithelial cells of turkeys. The crystals, which were thought to evolve from the rods, had a mean periodicity of 7.0 nm. In chicks between 1 and 3 days of age, but not in poults and ducklings, the duct epithelia displayed large intracytoplasmic deposits of glycogen which disappeared by the seventh day.