Seven years. Woolliness of adjacent diaphysial ends of femur and tibia indicating a pause in growth. Eight years. Etching of tibial articular surface begins. Nine years. Inequality of vertical growth of osseous tissues in the femoral epicondyles is well marked, the medial increasing more rapidly than the lateral. Ten years. Beak formation on femoral epiphysial shadow in trochlear area. Eleven years. Squaring of the lateral margins of the epiphysial shadows. Twelve years. Extension of bony epiphyses to overlap lateral margins of the shafts of tibia and femur. Thirteen years. Etching of the tibial spines. One or two instances will serve to show the freedom of skeletal maturity equally from the influence of aberrant skeletal dimensions and from anomalous conditions in other tissues such as excess of fat. (Radiographs of a thirteen year old giant and a ten year old fat boy were shown). [handwritten]Index is computed from length and breadth of tibia just below the knee. Dr. Heilman at Am. Museum is working out order of union of epiphyses in hand.