A surgical stapling apparatus, comprising: a first jaw member; a cartridge configured to selectively couple to the first jaw member, the cartridge having a cartridge housing defining a recess for housing a resilient member, the cartridge housing having a plurality of fasteners disposed in slots, the resilient member having a first position, a tip of the resilient member extending above a surface of the cartridge housing when the resilient member is in the first position, the resilient member having a second position in which the tip does not extend above the cartridge housing; a second jaw member having an anvil with staple forming depressions, the anvil having a locking member with a first position and a second position, an end of the locking member being aligned with the resilient member when the cartridge is coupled to the first jaw member; and a drive member movable from a retracted position to an advanced position for driving the fasteners toward the anvil, the locking member blocking movement of the drive member in the first position; the resilient member moving the locking member to the second position when the cartridge is attached to the first jaw member, the locking member allowing movement of the drive member when the locking member is in the second position.