The ornamental design for a portion of a saddle, as shown and described.
FIG. 1 is a left side perspective view of a portion of a saddle, showing my new design.
FIG. 2 is a right side perspective view thereof.
FIG. 3 is a rear elevational view thereof.
FIG. 4 is a front elevational view thereof.
FIG. 5 is a top plan view thereof.
FIG. 6 is a left side perspective view thereof.
FIG. 7 is a right side perspective view thereof.
FIG. 8 is an enlarged left side perspective view thereof.
FIG. 9 is an enlarged left side perspective view thereof taken from a different angle from that of FIG. 8; and,
FIG. 10 is an enlarged right side perspective view thereof.
The broken lines in the figures 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.