THE DEVELOPMENT OF THE PITUITARY GLAND IN FUNDULUS

¹ From the Department of Anatomy, University of Pennsylvania, and the Marine Biological Laboratory, Woods Hole, Massachusetts

The epithelial portion of the pituitary gland of Fundulus arises from ectodermal cells that proliferate to form a solid mass which comes to lie between the infundibulum and the pharynx. No lumen occurs in this mass of cells. After fibers from the infundibulum have entered this mass the cells are restricted to the peripherywhere they multiply to produce the pars glandularis of the adult gland. Those cells adjacent to the pars nervosa can be distinguished from the rest of the glandular portion and constitute the pars intermedia. The remainder of the pars glandularis is of uniform character. No "transitional region" can be distinguished in it either in the developing or in the adult gland. Since this portion forms the anterior part of the organ it may appropriately be called the pars anterior.