Valve Mole Trap. (fig. 64.) The mole, entering at a b, is prevented from returning; the valve (c) being made of such a length, and placed in such a position, as to admit of its opening inwards only, and, from the narrowing of the hole, the animal cannot turn itself. c, the valve on a larger scale; e d, a pin on which it moves: this pin is fixed into the tube at f g.