The ornamental design for a memorialbook, as shown and described.
FIG. 1 is a perspective view of a memorial book showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is an exploded perspective view thereof; shown in an opened position.
The broken lines showing hinges in FIGS. 2-4; 6 and 7; and an internal block in FIG. 8, are included for the purpose of illustrating portions of the memorial book that form no part of the claimed design.