The ornamental design for a frontportion of the swim mask having a projectionconfigured as a shark's dorsal fin, as shown and described.
FIG. 1 is a top and right side perspective view of a front portion of the
swim mask having a projection configured as a shark's dorsal fin showing
my new design; and,
FIG. 2 is a front elevational view thereof.
The broken lines environmental showing is for illustrative purposes only
and forms no part of the claimed design.