  We have studied the UV spectral behavior of the recurrent nova T Pyx during
16 years of IUE observations. We examined both the IUE line-by-line images and
the extracted spectra in order to understand the reality and the origin of the
observed spectral variations. The UV continuum of T Pyx has remained nearly
constant in slope and intensity over this time interval, without any indication
of long-term trends. The reddening determined from the UV data is E(B-V}=0.25
\pm 0.02. The best single-curve fit to the dereddened UV continuum is a
power-law distribution $\propto \lambda^{-2.33}$. The tail of this curve agrees
well with the B, V, and J magnitudes of T Pyx, indicating that the contribution
of the secondary star is negligible. One peculiar aspect of T Pyx is that most
emission lines (the strongest ones being those of CIV 1550 and HeII 1640) show
substantial changes both in intensity and detectability, in contrast to the
near constancy of the continuum. Several individual spectra display emission
features that are difficult to identify, suggesting a composite spectroscopic
system. We tentatively ascribe the origin of these transient emission features
either to loops and jets from the irradiated secondary or to moving knots of
the surrounding nebula that are (temporarily) projected in front of the system.
The inspection of all IUE line-by-line images has led to the detection of
emission spikes outside the central strip of the spectrum, which in some cases
seem associated to known emission features in the (main) spectrum. A comparison
with other ex-novae reveals a surprising similarity to the spectrum of the
very-slow nova HR Del, whose white dwarf primary has a mass that is allegedly
about one half that of T Pyx.
