The present invention provides devices for depositing objects into tissue of an animal. The devices include a cannula having a proximal-end and an opposite distal end insertable into tissue and defining an exit aperture. The cannula has a sidewall between the distal and proximal ends and defines a passageway in communication with the exit aperture. A distal retaining tab extends from an inner surface of the cannula and is positioned across at least a portion of the passageway adjacent the exit aperture. The distal tab has a first closed position blocking the passageway and a second open position wherein the tab is urged towards the sidewall to allow an object to pass. The tab is resilient to return to the first position after the object passes the tab. In some embodiments, the invention also includes a proximal retaining tab adjacent the proximal end of the cannula and positionable to block a portion of the passageway. The invention also a stylet that is slidable within the passageway to urge the objects out through the exit aperture.