Incubator

FIG. 1 is a top, front, right side perspective view of an incubator, showing my new design; FIG. 2 is a bottom, rear, right side perspective view thereof; FIG. 3 is a front elevational view thereof; FIG. 4 is a rear elevational view thereof; FIG. 5 is a left side elevational view thereof; FIG. 6 is a right side elevational view thereof; FIG. 7 is a top plan view thereof; and, FIG. 8 is a bottom plan view thereof. The evenly dashed broken lines illustrate portions of the incubator and form no part of the claimed design.