Abstract
The structure and cell types of the closely similar glands of Calamoichthys and Polypterus are described and a general comparison made with the teleost pituitary. The Polypterine gland shows some unsual features in the anatomical disposition of its parts and in the arrangement of its neurosecetory and vascular supply and an explanation of these differences is suggested, based on relative growth changes in later development, in order to include these glands in the evolutionary pattern of the actinopterygian pituitary.