The ornamental design for a specimenslidecover, as shown and described.
FIG. 1 is a perspective view of the top, front and right side of the specimen slide cover;
FIG. 2 is a perspective view of the bottom, front and right side thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a right elevational view thereof; and,
FIG. 7 is a left elevational view thereof.
The broken lines immediately adjacent the shaded areas represent the bounds of the claimed design while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.