Nictitans glands obtained from mongrel dogs were studied grossly and by regular histological and electron microscopic methods. Special stains including Periodic Acid-Schiff and Sudan Black B were used for the identification of specific macromolecular components.The nictitans gland is a compound tubulo--alveolar gland of apocrine type, although holocrine type of secretory activity is exhibitedby a portion of the gland. Two kinds of secretory materials were secreted by two different types of acinar cells in this gland.The main function of this gland is to secrete lubricant and to keep the eyes in a healthy state. It is thus considered as a supplementary structure to the lacrimal gland.Ball State UniversityMuncie, IN 47306