agedependent morphology of nadph diaphorasepositive amacrine cells in the mouse retina nadph diaphorasepositive amacrine cells nac were studied in retinal whole mount preparation of mice ranging from 1 day to 30 months of age following a peak in number and size during early development at postnatal day 14 their number and distribution remained well preserved up to senescence functional considerations include immunological vascular and neuromodulating aspects fenestration of the supraclinoid internal carotid artery a twentyeight year old woman presenting with subarachnoid hemorrhage was found at angiography to have a left anterior cerebralanterior communicating artery aneurysm also identified was a fenestration of the right supraclinoid internal carotid artery with an associated accessory middle cerebral artery this appears to be the second reported case of fenestration of the intracranial internal carotid artery fenestrations of cerebral vessels and their possible embryologic origins are briefly reviewed