A male infant with the Meckel syndrome was studied anatomically. The findings were compared to those from eight trisomy 13 cases to determine whether or not the superficial similarities between the two syndromes were matched by similarities in the internal variations. Emphasis was on the head and limbs. In the head, major differences were found in the nasal bones, mandible, and tongue. In the limbs, the skeletal variations were more severe in the Meckel syndrome infant, but he lacked the muscle variations diagnostic of trisomy 13.