Memoirs: The Development of the Pituitary of the Laboratory Mouse

1. A description is given of the development of the mouse pituitary, with particular reference to some obscure points in the general embryology of the mammalian gland. 2. The establishment of the neuro-ectodermal union of brain floor and stomodaeal roof precedes the appearance of Rathke's pouch; its importance and the effects of external and internal factors on pouch formation and closure are discussed. It is considered that the process cannot be entirely due to mechanical influences and differential growth. 3. The nervous lobe forms from a groove in the premammillary lamina which deepens and separates off. Later enlargement of the lobe is due to the reorganization of its cells, the appearance of fibres and a low but steady mitotic activity. 4. The establishment of the lateral lobes and the blood supply, the distribution of mitoses, the development of processes from the proximal into the nervous lobe and other points are recorded. I am again in debt to Professor E. A. Spaul, D.Sc., for reading the manuscript and for his invaluable discussion of the interpretations involved.