THERE have been numerous reports in the literature of arachnodactyly, but there are only a few cases reported in which there was an associated aortic aneurysm. Of over 300 cases of arachnodactyly (or Marfan's syndrome) in the literature, relatively few autopsy reports can be found. Marvel and Genovese1 reported a case of Marfan's syndrome with medionecrosis of the aorta and aneurysm formation in a 29-year-old Negro man (this is the 29th case). They also presented an excellent summary of the previous cases with autopsies reported in the American literature.* In 26 of the 29 cases they reviewed there were heart lesions. At 16 of the 26 autopsies aortic aneurysms were found, in 12 of which instances medionecrosis of Erdheim8 was described. Half of the persons with aortic aneurysm were men, and half were women. The youngest patient was a 14-year-old girl, and the oldest was a 52-year-old woman.