Abstract: Magazine for an immersed underwater crossbow containing a string and allowing for the rapid introduction by suction of the string and its natural arrangement by means of retracting means as well as its exit without difficulty.By pulling on the shank of the piston pump, a depression is produced within the magazine and the string rapidly enters the magazine across its end and, arranges itself naturally against the piston.One can thus arrange several meters without difficulty. The exit is accomplished in the same way.