. . "[0013] The invention is described in more detail below with reference, to the accompanying diagrammatic drawings, in which: [0014]FIG. 1 shows the disposition of the hollow structures which are to be joined by an anastomosis, and the apparatus components for doing so, at the point in time when formation of the anastomosis is about to begin; [0015]FIGS. 1a and 1 b are a vertical section and a plan" . .