  We present [O III] 4959,5007 emission line spectra (FWHM = 40 km/s) of the
Crab Nebula's northern ejecta `jet'. These data, along with a recent [O III]
image of the Crab, are used to build 3-dimensional models of the jet and
adjacent remnant nebulosity to better understand the jet's properties and
possible formation. We find that the jet's radial velocities range from -190 to
+480 km/s with transverse velocities from 1600 to 2650 km/s from base to tip.
The jet appears virtually hollow in [O III] emission with the exception of some
material at the jet's base where the it connects with the remnant. Our 3D
reconstructions indicate that the jet is elliptical in shape and slightly
funnel-like rather than a straight cylindrical tube as previously thought. At
the base of the jet we find evidence for a significant opening or "channel" in
the Crab's main nebula shell. Our analysis of the jet's expansion properties
and location supports the theory that the jet may simply represent the highest
velocity component of the Crab's N-S bipolar expansion.
