Left. Epileptic idiot, sixteen years old, mentally one year. Case 158 in Goddard's Feeble-mindedness (reference 34)- Center. Macrocephalic moro■ twent■four years old, mentally ten years. Case 278 in Goddard's Feeble-minded- ness. Macrocephaly is found occasionally in persons of normal intelligence, and in all grades of feeble-mindedness. The condition is caused by hydrocephaly or gliosis. Right. Microcephalic idiot, sixteen years old, mentally one year. Case 234 in Goddard's Feeble-mindedness. Microcephaly is rarely, if ever, seen in persons of normal intelligence. The condition is caused by early closure of the cranial sutures in the absence of the internal pressure caused by normal brain development. In rare instances