378 in left portion of sheet showing progression from the button as half circles in the top row to a full circle in the bottom rows, folded on perfs. between the third and forth rows (see CSS Catalog page 77)

378 in left portion of sheet showing progression from the button as half circles in the top row to a full circle in the bottom rows, folded on perfs. between the third and forth rows (see CSS Catalog page 77)