(a) Loss of member. Member lost ............................................ Number of weeks Arm ................................................................ 312 Leg ................................................................ 288 Hand ............................................................... 244 Foot ............................................................... 205 Eye ................................................................ 160 Thumb ............................................................... 75 First finger ........................................................ 46 Great toe ........................................................... 38 Second finger ....................................................... 30 Third finger ........................................................ 25 Toe other than great toe ............................................ 16 Fourth finger ....................................................... 15 If more than one phalange of a digit shall be lost, the period shall be the same as for the loss of the entire digit. If only the first phalange shall be lost, the period shall be one-half the period for loss of the entire digit. The period for loss or loss of use of two or more digits, or one or more phalanges of two or more digits, of a hand or foot, may be proportioned to the period for the loss of use of the hand or foot occasioned thereby, but shall not exceed the period for the loss of a hand or foot. If an arm or leg shall be amputated at or above the wrist or ankle, the period for such loss shall be in proportion to the period for the loss of the arm or leg. In the case of loss of binocular vision or of eighty per centum or more of the vision of an eye, the period shall be the same as for the loss of the eye.