The presence of groups of cells resembling squamous epithelium in the hypophysis cerebri, and the occurrence of tumors in the hypophysis and infundibulum, the histologic appearance of which resembles that of these rests, are of interest because of the support they afford to Cohnheim's well known embryonal theory of the origin of new growths. It is my purpose in this paper to report the results of examination of the normal hypophysis removed at necropsy in a group of fifty-five cases. The infundibular region was studied in serial sections for squamous epithelial rests.
As knowledge of the development of the hypophysis is essential for an understanding of these rests, a short description of the steps in the development of the gland, in particular of the pars buccalis, will first be given. Throughout this paper, Tilney's nomenclature1 for the different parts of the hypophysis will be followed.
The hypophysis is developed