An account is given of the vascularization of the pituitary stalk and of the associated region of the hypothalamus in the minnow. It is pointed out that, making allowance for the fact that the teleosts are widely separated from the main line of vertebrate ascent, the pattern of this vascularization has something in common with that of a median eminence. A particular feature is the existence of a capillary bed in the floor of the infundibular recess and this is shown to have a close topographical relationship with cells containing granules which are intensely stained by chrome-alum-haematoxylin. These is some evidence that these may be secretory cells and that their products pass into the blood stream and into the third ventricle.